nsect  Enemies 


R  BEET 


ON 
i      i  i  Department 


THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 

LOS  ANGELES 


Principal  Insect  Enemies 


SUGAR  BEET 


IN   THE  TERRITORIES  SERVED  BY 

The  Great  Western  Sugar  Company 


BY 

ASA  C.  MAXSON 

In  Charge,  Experimental  Department 


Published  by 

AGRICULTURAL  DEPARTMENT 

THE  GREAT  WESTERN  SUGAR  COMPANY 

DENVER,  COLORADO 

1920 


-Afftcoffure 


PREFACE 

Some  damage  is  done  by  some  pest  somewhere  every  year,  causing 
some  loss  to  individual  farmers.  Fortunately,  we  have  been  free  so  far 
from  pests  damaging  very  large  areas  in  any  one  year,  and  it  is  confidently 
hoped  that  this  will  always  be  the  case  in  the  territory  served  by  this  Com- 
pany. Nevertheless,  it  seems  wise  to  have  on  hand  all  the  information 
necessary  to  enable  growers  to  apply  proper  measures  in  case  of  emergency. 
'  There  are  available  a  number  of  bulletins  and  books  published  by  the 
Department  of  Agriculture,  Agricultural  Colleges  and  others,  dealing  with 
insect  pests  damaging  to  sugar  beets,  but  it  has  been  thought  of  interest 
and  value  to  beet  growers  to  have  this  information  presented  in  one  book 
and  with  due  regard  to  local  conditions. 

While  it  is  hoped  that  this  Bulletin  will  be  of  valuable  assistance  to 
the  grower  of  sugar  beets  by  presenting  the  best  known  methods  of  pre- 
venting injury  and  controlling  insects  which  damage  this  crop,  it  seems 
desirable  to  impress  upon  him  the  fact  that  there  is  no  magical  method,  no 
patent  medicine,  which  can  be  quickly  and  easily  applied. 

Good  farming,  as  taught  by  local  experience,  practiced  con- 
sistently every  year,  will  produce  bigger  yields  of  beets  and  min- 
imize the  damage  done  by  insects  or  beet  diseases. 

For  the  benefit  of  those  wishing  to  study  the  subject  more  completely, 
scientific  names  of  insects,  other  invertebrate  animals,  and  plants  discussed, 
have  been  given  in  the  Appendix,  pages  138  to  146,  together  with  credit 
for  determination.  Free  use  has  been  made  of  the  literature  of  beet  insects 
and  credit  given  where  it  has  been  quoted. 

This  Bulletin  has  been  prepared  by  Mr.  A.  C.  Maxson,  Entomologist 
in  charge  of  the  Company's  Experimental  Farm  at  Longmont,  Colorado. 

Credit  is  due  Miss  Caroline  M.  Preston  for  reproducing  the  insects 
for  the  colored  plates. 

THE  GREAT  WESTERN  SUGAR  COMPANY 


816211 


TABLE  OF  CONTENTS 

Introduction 1 

Outline  of  the  Bulletin 3 

Key  for  Determining  Insect  Injury  to  Sugar  Beets: 

Explanation  of  Key 4 

The  Key 5 

Colored  Plates 11 

CHAPTER  I 

Insects  in  General 29 

Structure 29 

Development 29 

The  Egg 30 

The  Larva 30 

The  Pupa 30 

The  Adult 30 

The  Integument 30 

Classification 31 

Root  Feeders 31 

Leaf  Feeders 31 

Biting  Insects 31 

Sucking  Insects 31 

Methods  ofControl 31 

Natural  Methods 31 

Crop  Rotation 31 

Plowing 32 

Late  Planting 32 

Burning 32 

Clean  Culture 32 

Artificial  Methods — Insecticides 32 

Control  of  Biting  Insects 32 

Control  of  Sucking  Insects — Contact  Poisons 33 

Repellents 33 

Sprayers 33 

Traction  Sprayer 33 

Care  of  Sprayers 34 

Knapsack  Sprayer 36 

Hand  Sprayer 36 

Home-made  Sprayer 37 

Paris  Green,  Caution  Regarding  the  Handling  of 37 

iii 


Table  of  Contents 

CHAPTER  II 

Page 

Root  Feeders 38 

A.  Biting  Root  Feeders 38 

1 .  Cutworms ^8 

a.  Western  Army  Cutworm 41 

b.  Pale  Western  Cutworm 45 

c.  Variegated  Cutworm 47 

2.  White  Grubs 48 

3.  Wireworms 52 

B.  Sucking  Root  Feeders 55 

1 .  Sugar  Beet  Root-louse 55 

2.  Sugar  Beet  Nematode 59 

3.  Root-knot  Nematode  or  Gallworm 64 

CHAPTER  III 

Leaf  Feeders 67 

A.  Biting  Leaf  Feeders 67 

1 .  Leaf-eating  Caterpillars 67 

a.  Sugar  Beet  Webworm 67 

b.  True  Army  Worm 78 

c.  Alfalfa  Looper 81 

d.  Alfalfa  Webworm 84 

e.  Yellow-bear  Caterpillar 86 

f.  Zebra  Caterpillar 87 

2.  Leaf-eating  Beetles 88 

a.  Larger  Sugar  Beet  Leaf-beetle  or  Alkali-beetle 89 

b.  Western  Beet  Leaf-beetle 90 

c.  Flea-beetles 91 

c-1.  Banded  Flea-beetle 92 

c-2.  Potato  Flea-beetle 93 

c-3.  Three-spotted  Flea-beetle 93 

d.  Spinach  Carrion-beetle 94 

e.  Blister-beetles 96 

3.  Grasshoppers 98 

a.  Two-lined  Hopper 100 

b.  Differential  Hopper 100 

c.  Red-legged  Locust 100 

4.  Field  Crickets 109 

5.  Leaf-miners 110 

a.  Beet  or  Spinach  Leaf-miner. . .  .110 


Table  of  Contents 

Leaf  Feeders — Continued  Page 

B.  Sucking  Leaf  Feeders Ill 

1 .  Aphids  or  Plant-lice Ill 

a.  Green  Peach-aphis 1 16 

b.  Black  Beet-seed  Louse 117 

2.  True  Bugs 1 19 

a.  False  Chinch  Bug 119 

b.  Tarnished  Plant-bug 122 

3.  Leaf-hoppers 123 

a.  Sugar  Beet  Leaf-hopper 1 23 

b.  Clover  Leaf-hopper 126 

c.  Eutettix  strobi  Fitch 128 

CHAPTER  IV 

Beneficial  Insects 129 

A.  Predacious  Insects 130 

1.  Ground  Beetles 130 

a.  Fiery  Hunter 130 

b.  Bombardier-beetles 130 

2.  Tiger-beetles 131 

3.  Lady-beetles  or  Lady-bugs 132 

4.  True  Bugs 132 

a.  Assassin-bugs 133 

b.  Ambush-bugs 133 

c.  Stink-bugs 133 

5.  Lace-winged  Flies 133 

6.  Wasps 134 

a.  Digger-wasps 134 

a-1.  Family  Scoliidae 134 

a-2.  Spider-wasps 134 

a-3.  Thread-waisted  wasps 134 

b.  Solitary  Wasps 135 

B.  Parasitic  Insects 135 

1.  Ichneumon-flies 136 

2.  Braconids 136 

3.  Chalcis-flies 137 

Appendix 138 

Bibliography 147 

Index..                                                                                                       .  149 


LIST  OF  TEXT  FIGURES 

Page 

Fig.    1     A  good  type  of  traction  sprayer  for  field  use.     (Original) 33 

Fig.    2    Knapsack  sprayer.     (Original) 36 

Fig.    3    Hand  sprayer.     (Original) 36 

Fig.    3-a  A  Home-made  sprayer 

Fig.    4    Scales  from  wing  of  moth  of  western  army  cutworm,  highly 

magnified.       (Original) 42 

Fig.     5     Adult  snapping-beetle,  Alans  ocutatus.     The  larvae  of  this 

beetle  feed  upon  decaying  wood.     (Original) 52 

Fig.    6    A  sugar  beet  infested  with  sugar  beet  namatodes.     The  white 
bodies  of  the  female  nematodes  can  be  seen  clinging  to  the 

rootlets.     (Original) 60 

Fig.  7  A  sugar  beet  affected  with  curly-top,  showing  the  character- 
istic dense  mass  of  rootlets.  (After  C.  O.  Townsend, 
Farmers'  Bulletin  No.  122,  U.  S.  Department  of  Agri- 
culture)   60 

Fig.  8  Small  sugar  beets  infested  with  the  root-knot  nematode.  The 
bead-like  swellings  on  the  small  roots  and  the  enlarge- 
ments of  the  main  root  are  caused  by  the  nematodes. 

(Original) 64 

Fig.    9    Sugar  beet  badly  damaged  by  webworms 69 

Fig.  10    Sugar  beets  badly  damaged  by  webworms 70 

Fig.  1 1     Field  of  sugar  beets  showing  work  of  the  sugar  beet  webworm. 

(Original) 71 

Fig.  12    Result  of  spraying — left,  unsprayed;  right,  sprayed 73 

Fig.  13  A  portion  of  the  compound  eye  of  a  tiger-beetle,  highly  mag- 
nified. (Original) 76 

Fig.  14    Cross     section     through     burrow    of    the    solitary    wasp. 

(Original) 78 

Fig.  15    Hopper  dozer.     (After  Charles  R.  Jones,  Bulletin  No.  233, 

Colorado  Agricultural  Experiment  Station) 102 

Fig.  16    Exposed  grass  roots,  showing  grasshopper  eggs  and  larvae  of 

the  ground  beetle,  Amara  obesa.     (Original) 106 

Fig.  17    Hair    worm   escaping    from    a    parasitized    ground    beetle. 

(Original) 107 

Fig.  18    The  hair  worm  shown  in  Figure  17,  after  it  had  escaped  from 

the  beetle.     (Original) 108 

Fig.  19    Grasshoppers  killed  by  the  fungous  disease,  Empusa  grylli. 

(Original) .    109 


List  of  Text  Figures 

Page 

Fig.  20  An  exposed  colony  of  plant-lice  on  a  common  roadside  weed. 

(Original) 112 

Fig.  21     Leaves  of  white  ash  curled  by  a  plant-louse.     (Original) 112 

Fig.  22  Gall  of  sugar  beet  root-louse  on  leaves  of  narrow-leaf  cot- 

tonwood.  (Original) 113 

Fig.  23     A  common  wingless  aphid;  honey  tubes  at  "A".    (Original) . .    113 

Fig.  24  A  branch  of  Euonymus  species,  showing  star-shaped  fruit. 

(Original) . 118 

Fig.  25  Sugar  beet  showing  characteristic  curling  of  leaves  caused  by 
curly-top.  (After  Harry  B.  Shaw,  Bulletin  No.  181,  U. 
S.  Bureau  of  Plant  Industry) 124 

Fig.  26  Cross  section  of  sugar  beet,  showing  darkening  of  rings  caused 
by  curly-top.  (After  C.  O.  Townsend,  Bulletin  No.  122, 
U.  S.  Bureau  of  Plant  Industry) 125 

Fig.  27  Entrance  to  burrow  of  tiger-beetle  larva.  There  is  never  any 

loose  soil  at  the  entrance  to  these  burrows.  (Original) . .  131 

Fig.  28  Same  burrow  as  shown  in  Figure  27,  with  head  of  larva  resting 
on  level  with  the  surface,  ready  to  seize  a  victim.  (Orig- 
inal)   131 

Fig.  29  Nest  of  a  mud-dauber,  taken  from  rafter  of  an  out-building. 

(Original) 135 

Fig.  30  A  cabbage-worm  killed  by  the  larvae  of  a  Braconid,  the 
cocoons  of  which  are  fastened  to  the  window  screen  near 
it.  (Original) 136 


INTRODUCTION 

The  impression  may  be  gained  that  the  sugar  beet  is  especially 
liable  to  insect  injury  because  of  the  bringing  together  of  so  much  on  the 
subject.  However,  this  is  not  the  case.  A  study  of  crop  insects  shows 
that  most  crops  have  an  equal  number  of  insect  enemies  and  many  have 
more.  It  should  be  emphasized  that  everything  known  to  good  farming 
practice  in  beet  culture,  such  as  rotation  of  crops,  manuring,  clean  culture, 
and  timeliness  of  plowing  and  irrigating,  tends  to  minimize  damage  by 
insects. 

OUTLINE  OF  THE  BULLETIN 

By  knowing  in  advance  the  structural  plan  of  the  Bulletin,  reference 
can  more  readily  be  made  to  any  desired  part.  Hence  an  outline  is 
given  on  page  3.  Furthermore,  the  use  of  this  Outline  in  conjunction 
with  the  "Key  for  Determining  Insect  Injury  to  Sugar  Beets"  (pages  5 
to  8)  may  aid  in  identifying  insects.  For  example,  if  it  is  known  that 
damage  is  being  done  to  the  leaves  of  the  beets  and  that  the  insects  caus- 
ing it  are  "Biting"  insects,  and  if  it  is  known  that  they  are  not  beetles  or 
grasshoppers,  then  it  can,  for  practical  purposes,  be  concluded  that  the 
damage  is  being  caused  by  either  leaf-miners  or  caterpillars,  and  by 
referring  to  the  text  cited,  a  conclusion  can  in  most  cases  be  drawn  regard- 
ing the  particular  insect  causing  the  damage.  If  one  of  the  suspected 
insects  has  been  caught,  the  Colored  Plates  (See  pages  11  to  27) 
will  greatly  facilitate  its  identification. 

KEY  FOR  DETERMINING  INSECT  INJURY  TO  SUGAR  BEETS 

In  order  to  facilitate  the  use  of  this  Bulletin  for  reference  purposes, 
a  short  "Key  for  Determining  Insect  Injury  to  Sugar  Beets"  has  been 
constructed.  (See  pages  5  to  8.)  If  the  nature  of  the  insect  damage  is 
known,  reference  to  this  "Key"  should  enable  one  to  determine  the  gen- 
eral class  of  insect  doing  the  damage,  if  not  the  particular  insect.  By 
looking  up  the  descriptive  pages  cited  in  the  "Key",  and  by  checking 
the  Colored  Plates  against  the  suspected  insect,  if  one  has  been 
caught,  a  reasonably  strong  case  can  probably  be  established. 

COLORED  PLATES 

It  took  the  artist  three  seasons  to  complete  the  drawings  from  which 
the  Colored  Plates  were  made.  Every  insect  was  drawn  directly  from 
a  live  specimen,  and  the  form  and  colors  are  true  to  life. 

Some  of  these  colored  pictures  were  enlarged.  In  nearly  all  such 
cases  a  small  black  and  white  outline  at  the  left  or  right  of  the  colored 
picture  shows  the  natural  size  of  the  specimen.  The  exceptions  are 
clearly  noted  on  the  title  pages. 

Pictures  as  well  prepared  as  these  carry  descriptions  much  more 
quickly  and  accurately  than  words,  especially  to  persons  not  trained  to 
think  in  entomological  terms. 

I 


Introduction 

The  main  purpose  of  all  this  care  in  preparing  these  Colored  Plates 
is  to  enable  the  reader  to  identify,  in  the  easiest  and  most  positive  manner 
possible,  any  specimens  he  may  have  procured. 

The  title  page  opposite  each  plate  gives  the  name  of  each  specimen 
and  indicates  the  pages  of  the  Bulletin  on  which  it  is  discussed. 

Additional  help  in  locating  the  pages  on  which  any  individual  insect 
is  discussed  may  be  had  from  the  Outline  of  the  Bulletin  (page  3),  the 
"Key  for  Determining  Insect  Injury  to  Sugar  Beets"  (pages  5  to  8), 
the  Appendix  (pages  138  to  146),  and  Index  (pages  149  to  157). 

THE  APPENDIX 

The  Appendix  (pages  138  to  146)  contains  an  alphabetical  list  of  the 
popular  names  of  insects  and  plants  discussed,  together  with  their  scien- 
tific names,  credit  for  their  determination,  and  illustration  and  page 
references.  The  Appendix  is  mainly  for  the  benefit  of  those  wishing  ^to 
study  the  subject  more  fully  than  has  been  done  in  this  Bulletin. 

THE  INDEX 

The  Index  will  be  found  at  the  back  of  the  book,  on  pages  149 
to  157. 

THREE  METHODS  FOR  LOCATING  DESIRED  TEXT 

1.  If  you  know  the  name  of  the  insect,  use  the  Index  (pages  149 
to  157)  or  the  Appendix  (pages   138  to  146)  to  find  the  pages  of  the 
Bulletin  on  which  it  is  discussed. 

2.  If  you  know  the  nature  of  the  damage,  but  not  the  name  of  the 
insect  doing  it,  use  the  "Key  for  Determining  Insect  Injury  to  Sugar 
Beets"  (pages  5  to  8)  or  the  Outline  (page  3). 

3.  If  you  have  one  of  the  suspected  insects,  but  do  not  know  its 
name,  use  the  Colored  Plates  (pages  1 1  to  27). 

Use  both  Methods  2  and  3  when  possible,  to  make  identification 
more  positive. 

In  case  of  doubt  as  to  the  identity  of  an  insect  or  other  specimen, 
or  as  to  the  nature  of  an  injury,  competent  advice  can  always  be  obtained 
by  consulting  the  authorities  of  the  Agricultural  College,  the  County 
Agents,  or  The  Great  Western  Sugar  Company's  fieldmen. 

REFERENCE  FIGURES 

The  small  elevated  figures  found  occasionally  throughout  the  text 
alter  the  mention  of  some  insect,  refer  to  the  corresponding  marginal 
figure  in  the  Appendix.  The  purpose  of  the  reference  is  to  connect  the 
particular  species  to  its  scientific  name. 

BIBLIOGRAPHY 

™/ Bibliography  (pages  147  and  148)  contains  a  list  of  Publications 
>n  related  subjects  Some  of  these  have  been  drawn  upon  in  the  com- 
pilation of  this  Bulletin,  and  credit  given  in  the  text. 


Introduction 


OUTLINE  OF  THE  BULLETIN 

INTRODUCTION 

Outline  of  the  Bulletin 

Key  for  Determining  Insect  Injuring  Sugar  Beets 

Colored  Plates 


CHAPTER  I 


Insects  in  General 


(a)  Structure 

(b)  Development 

(c)  Classification 

(d)  Methods  of  Control 


CHAPTER  II 

Root  Feeders (a)  Biting (1)  Cutworms 

(2)  White  Grubs 

(3)  Wireworms 

(b)  Sucking (1)  Sugai  Beet  Root-louse 

(2)  Sugar  Beet  Nematode 

(3)  Root-knot  Nematode  or 

Gallworm 

CHAPTER  III 
Leaf  Feeders (a)  Biting (1)  Caterpillars 


(b)  Sucking. . . . 


(2)  Beetles 

(3)  Grasshoppers 

(4)  Field  Crickets 

(5)  Leaf-miners 

.  (1)  Aphids  or  Plant-lice 

(2)  True  Bugs 

(3)  Leaf -hoppers 


CHAPTER  IV 


Beneficial  Insects.. 

.  .  (a)  Predac  ious  (  1  ) 

Beetles 

(2) 
(3) 
(4) 
(b)  Parasitic  (1) 

True  Bugs 
Lace-winged  Flies 
Wasps 
Ichneumon-flies 

(2) 
(3) 
APPENDIX 
BIBLIOGRAPHY 
INDEX 

Braconids 
Chalcis-flies 

Introduction 


EXPLANATION  OF  KEY  FOR  DETERMINING  INSECT 
INJURY  TO  SUGAR  BEETS 

The  method  of  using  the  Key  (pages  5  to  8)  is  illustrated  below 
by  imagining  a  case  of  injury  and  following  it  through  the  Key  until 
we  come  to  the  point  where  we  get  a  clue  to  the  insect  causing  the  damage. 

Example:  In  going  through  the  field  while  the  thinners  are  at  work, 
we  notice  a  beet  here  and  there  which  is  wilted  and  cut  off  just  below 
the  surface  of  the  ground.  Take  your  Key  and  begin  at  "A."  This 
says  that  the  leaves  of  the  plant  are  wilted  while  those  of  the  surround- 
ing plants  remain  normal.  This  is  true  of  the  plants  we  found,  so  we  read 
what  comes  under  "1."  As  our  beet  is  cut  off  below  the  surface  of  the 
ground  "1"  fits  our  case,  so  we  continue  to  "a"  and  read:  "Plants  small. 
Damage  occurring  before  or  shortly  after  blocking  and  thinning".  As  the 
thinners  are  at  work  in  our  field  this  again  fits  our  case,  so  we  pass  on 
to  the  single  star  (*).  Here  we  read:  "Plants  cut  off  at  or  just  below 
the  surface  of  the  ground, "  etc.  This  is  our  case  exactly,  and  at  the  end 
we  read:  "Look  for  Cutworms."  Thus  the  Key  indicates  that  cut- 
worms are  at  work  on  our  beets  and  refers  us  to  pages  38  to  48  of  the 
Bulletin,  where  .this  insect  is  discussed. 

Let  us  suppose  that  when  we  read  the  paragraph  under  the  single  star 
(*)  we  found  that  this  did  not  describe  -our  beet.  We  would  then  pass 
on  to  the  double  star  (**),  and  if  the  beet  we  have  has  been  injured  by 
any  of  the  insects  discussed  in  this  Bulletin  this  paragraph  should  describe 
the  way  it  is  injured. 

If  the  injury  was  not  indicated  by  a  wilting  of  the  leaves  we  pass 
from  the  capital  "A"  to  capital  "  B",  on  page  6,  and  if  this  does  not  fit 
our  case  we  pass  on  through  the  capital  letters  until  we  do  find  the  de- 
scription. When  we  find  it  we  pass  through  the  other  steps  which  are 
indicated  by  figures,  small  letters,  etc.,  until  we  come  to  the  place  where 
the  insect  causing  the  injury  is  named. 

While  this  Key  may  not  fit  all  cases  exactly,  yet  it  should  enable 
one  to  determine  quite  closely  what  insect  is  causing  the  injury  noticed. 
Then  if  the  discussion  of  this  insect  and  the  nature  of  its  injury  are  read 
and  the  insect,  if  one  is  secured,  is  compared  with  the  pictures  in  the 
Colored  Plates,  there  should  be  little  difficulty  encountered  in  identifying 
the  culprit. 

In  case  of  doubt  competent  advice  can  always  be  obtained  by  con- 
sulting the  authorities  of  the  agricultural  colleges,  county  agents  or  the 
sugar  company's  fieldmen. 


Introduction 


KEY  FOR  DETERMINING  INSECT  INJURY  TO  SUGAR  BEETS 

A.  Leaves  of  plant  wilted  while  those  of  surrounding  plants  re- 
main normal. 

1.  Plants  cut  off  above  the  surface  of  the  ground,  at  varying  depths 

below,  or  with  portions  of  the  root  surface  eaten  away,  leaving 
shallow  depressions  or  deep  pits  with  darkened  walls. 

a.  Plants    small.     Damage    occurring    before    or    shortly    after 

blocking  and  thinning. 

*  Plants  cut  off  at  or  just  below  the  surface  of  the  ground. 

Damage  most  apt  to  occur  where  beets  follow  alfalfa 
or  grain,  timothy  or  abandoned  crops,  and  on  fields  ad- 
jacent to  alfalfa. 

Look  for  Cutworms  (pages  38-48). 

**  Plants  cut  off  an  inch  or  so  below  the  surface  of  the 
ground.  Tip  of  root  as  pulled  from  the  ground  dark, 
almost  black.  Damage  most  apt  to  occur  where  beets 
follow  alfalfa,  sod,  pasture  or  meadow. 

Look  for:  White  Grubs  (pages  48-52) ; 
Wireworms  (pages  52-54). 

b.  Beets  larger.     Damage  occurring  from  time  roots  attain  the 

size  of  one's  finger  until  harvest. 

*  Plants  always  cut  off  above  surface  of  ground  or  with 

deep  cavities  pecked  into  the  crowns.  Damage  most 
apt  to  occur  near  standing  alfalfa  or  waste  land  over- 
grown with  weeds  or  other  tall  growth. 

Damage  caused  by  Pheasants. 
**  Plants  never  cut  off  above  the  surface  of  the  ground. 

0  Portions  of  root  surface  eaten  away,  leaving  shallow 
depressions  with  rough  darkened  surface.  Root 
often  entirely  eaten  off  several  inches  below  the 
surface  of  the  ground.  Damage  usually  occurring 
where  beets  follow  sod,  pasture  or  meadow,  or  on 
river  bottom  land. 

Look  for  White  Grubs  (pages  48-52). 

00  Portions  of  root  surface  eaten  away,  leaving  small, 
deep,  dark-walled  pits.  Roots  of  large  beets  never 
entirely  eaten  off.  Damage  most  apt  to  occur 
where  beets  follow  alfalfa,  sod,  pasture  or  meadow. 

Look  for  Wireworms  (pages  52-54). 

2.  Plants  not  cut  off.     Portions  of  root  surface  not  eaten  away. 

Leaves  often  dull,  dark  green,  as  though  plants  were  suffering 
from  lack  of  moisture;  or  leaves  yellowish  green. 

5 


Introduction 

a.  Only  young  heart  leaves  wilted.      Wilting  usually  most  appar- 

ent at  tip  of  leaves.     Later  these  tips  become  dry  and  brown. 
Look  for  Tarnished   Plant-bugs  (pages 
122-123). 

b.  Entire  plant  more  or  less  wilted. 

*  Root  either  covered  with  whitish  substance  or  with  abnor- 
mal development  of  fine  roots  or  wart-like  swellings. 

0  Root  more  or  less  covered  with  a  white  mould-like 
substance.  Many  whitish-yellow  lice  mixed  with 
this  substance.  Lice  present  in  nearly  every 
field  regardless  of  previous  crop.  Damage  more 
apt  to  be  severe  in  dry  years  than  wet. 

Sugar    Beet  Root-lice  (pages  55-59). 

00  Root  with  abnormal  development  of  fine  rootlets. 
Many  small  pearly-white  bodies  clinging  to  these 
rootlets.  (See  Figure  9,  Plate  III,  Page  15  and 
Figure  6,  Page  60).  In  late  fall  many  of  these 
bodies  become  rich  brown  in  color.  Injury  most 
apt  to  occur  on  old  beet  ground. 

Sugar  Beet  Nematode  (pages  59-64). 

000  Roots  with  wart-like  swellings.  Rootlets  with 
small,  almost  round  swellings  resembling  beads  on 
a  string.  (See  Figure  8,  Page  64).  Injury  most 
apt  to  occur  on  old  beet  ground. 

Root-knot     Nematode     or     Gallworm 
(pages  64-66). 

**  Root  normal.     Not  as  above. 

0  Damage  usually  most  severe  in  fields  near  poor 
stands  of  alfalfa  overrun  by  shepherd 's-purse, 
fanweed  and  other  weeds  of  the  mustard  family. 
Fields  adjacent  to  waste  land  overgrown  with 
these  weeds  very  apt  to  be  damaged,  also,  as  weeds 
begin  to  ripen. 

Look  for  False  Chinch  Bugs  (pages  1 19- 

B.  Leaves  dull  green,  light  yellow,  or  blotched  with  whitish  green 
or  purple. 

1.  Leaves  dull  green,  as  though  plants  were  suffering  from  lack  of 
moisture.  In  severe  cases  leaves  become  light  yellowish  green. 
Plants  making  poor  growth. 

Look  for :  Sugar  Beet  Root-lice  (pages 

55-59); 
Nematodes  (pages  59-66). 


Introduction 

2.  Leaves  blotched  with  whitish  green.     Not  abnormally  curled. 

Look  for:  Plant-lice  (pages  111-116), 
Leaf-hoppers  (pages  123-128). 

3.  Leaves  blotched  with  purple  (Figure  1,  Plate  VIII,  Page  25). 

Look  for  Leaf-hoppers  (pages  123-128). 

C.  Leaves  with  portions  of  blade  or  stem  eaten  away.     Sometimes 
crowns  of  beets  eaten  also. 

1.  Leaves   eaten  full    of  small  holes  (Figure  1,  Plate  IV,  Page  17). 

Injury  most  apt  to  occur  during  spring  and  early  summer. 

Look  for  Flea-beetles  (pages  91-93). 

2.  Leaves  more  or  less  completely  eaten,  or  portions  eaten  from  mar- 

gins (Figure  11,  Plate  III,  Page  15V 

a.  Leaves  often  more  or  less  covered  with  a  fine  whitish  web. 

Damage  caused  by  worms  about  one  inch  long  when  fully 
grown.  Worms  very  active,  throwing  themselves  from  the 
plant  when  disturbed.  Often  hanging  from  leaf  by  a  single 
thread  of  web,  especially  when  young. 

*  Worm  dark  green,  striped,  several  dark  circular  spots  on 
each  segment  of  the  body  (Figure  6,  Plate  V,  Page 
19).  Web  when  present  usually  on  blade  of  leaf  near 
its  base.  Heart  leaves  usually  eaten  last.  Excrement 
of  worms  scattered  over  leaves  in  form  of  small  dark 
pellets. 

Sugar  Beet  Webworms  (pages  67-78). 

**  W'orm  lighter  than  webworm.  A  pink  or  flesh-colored 
stripe  on  each  side  (Figure  1,  Plate  VI,  Page  21). 
Web  often  among  heart  leaves.  A  long  tube  leading 
from  web  to  clods  on  the  surface  of  the  ground.  Worm 
usually  concealed  at  end  of  this  tube  when  not  feeding. 

Alfalfa  Webworms  (pages  84-85). 

b.  Leaves  not  webbed. 

*  Damage  occurring  during  spring  and  early  summer,  while 
beets  are  still  small. 

0  Damage  usually  most  severe  on  wet  alkali  land  or 
near  such  land. 

Look  for  Alkali-beetles  (pages  89-90). 

00  Damage  not  associated  with  alkali  land.  Usually 
most  severe  near  alfalfa,  ditch  banks,  fence  rows 
or  waste  land.  Edges  of  leaves  eaten.  In  severe 
cases  entire  plant  destroyed. 

Look  for  Spinach  Carrion-beetles  (pages 
94-95). 


Introduction 
**  Damage  usually  occurring  during  midsummer  or  later. 

0  Damage  most  severe  on  wet  alkali  land  or  near  such 
land.  Tender  portion  of  leaf  eaten,  only  a  net- 
work of  veins  remaining,  which  soon  become  dry 
and  brown. 

Look  for  Alkali-beetles  (pages  89-90). 

0  °  Damage  usually  most  severe  at  borders  of  field/iear 
wild  land,  waste  land,  ditch  banks  and  fence  rows 
where  grasshoppers  are  numerous,  or  near  alflafa 
or  waste  land  overrun  with  sweet  clover,  or  near 
grain  fields. 

Look  for:  Grasshoppers  (pages  98-109); 
Alfalfa    Loopers    (pages    81- 
84); 

Western     Army     Cutworms 
(pages  41-45). 

000  Damage  usually  slight,  only  a  beet  leaf  here  and 
there  being  eaten.  Not  confined  to  border,  but 
occurring  throughout  entire  field. 

Look  for :  Yellow-bear  Caterpillars  (pages 
86-87) ; 

Zebra  Caterpillars  (pages  87-88); 
Variegated  Cutworms  (pages  47-48). 

D.  Leaves  very  much  curled  and  distorted.  Veins  much  enlarged, 
often  bearing  cone-shaped  points  (Figure  5,  Plate  VIII,  Page 
25).  Root  small  and  stunted.  Rootlets  abnormally  de- 
veloped (Figure  7,  Page  60).  Crown  often  covered  with  a 
sticky  syrup-like  substance.  Curly- top  (pages  124-125). 

Look  for  Sugar  Beet  Leaf-hoppers  (Pages 
123-126). 


COLORED  PLATES 


PLATE  I  Page 

Fig.   1  Western  Army  Cutworm,  Chorizagrotis  auxiliaris  Grt 41 

2  Western  Army  Cutworm,  pupa 41 ,  46 

3  Western  Army  Cutworm,  adult  moth 41,  42,  88 

4  Western  Army  Cutworm,  wing  of  dark  individual 41,  42 

5  An  Ichneumon-fly  parasite  of  the  Western  Army  Cutworm, 

Amblyteles  longula  Cress.     (Enlarged) 43,  136 

6  A  Braconid  parasite  of  the  Western  Army  Cutworm — Mic- 

rogaster  species  (Enlarged) 43,  136,  137 

7  Cocoon  of  Microgaster  species  (Enlarged) 44,  136,  137 

8  Chalcis-fly  parasite  of  cutworms,  Berecyntus  bakeri  bakeri 

Howard  (Enlarged) 44,  137 

9  Pale  Western  Cutworm,  Porosagrotis  orthogonia  Morr 45 

10  Pale  Western  Cutworm,  adult  moth 45,  46 

1 1  Eggs  of  Pale  Western  Cutworm  (Enlarged) 42,  45,  46 

12  Egg  of  Pale  Western  Cutworm  (Natural  size) 42,  45,  46 

13  Wireworm 52,  53 

14  Last  segment  of  Wireworm  (Enlarged) 52,  53 

1 5  Wireworm  pupa 52,  54 

16  Adult  Wireworm,  Hemicrepidius  memnonius  Herbst .  .  .  .52,  53,  54 

17  Adult  Wireworm  (Enlarged) 52,  54 

18  Larva  of  adult  Wireworm  shown  in  Figure  17 52,  53 

19  White  Grub 48,  51 

20  A  small  white  grub  which  feeds  upon  decayed  vegetable 

matter 48,  5 1 

2 1  True  Army  Worm 78,  80 

22  True  Army  Worm 78,  80 

23  Adult  White  Grub,  Ligyrus  gibbosus  De  G 48,  51 

24  Pupa  of  True  Army  Worm 78,  80 

25  Adult  True  Army  Worm 78,  80 

Note:  In  case  of  enlargement,  a  natural  size  black  and 
white  outline  drawing  is  shown  beside  the  colored  picture.  Ex- 
ceptions to  this  plan  on  Plate  I  are  Figures  7  and  14. 


10 


PLATE.  I 


fif./3 


II 


PLATE  II 

Sugar  Beet  Root-louse,  Pemphigus  betas  Doane  Page 

Fig.   1  Newly  hatched  louse  feeding  on  cottonwood  leaf  (See  "A").  55,  58 

2  Newly  hatched  louse  (Enlarged) 55,  57 

3  Upper  side  of  leaf  after  gall  becomes  closed 55,  58 

4  Side  view  of  young  gall 55,  58 

5  Fully  developed  gall 55,  58 

6  Full  grown  stem-mother  (Enlarged) 55,  58 

7  Full    grown    second    generation    louse    (Spring    migrant) 

(Enlarged) 55,  58 

8  Antenna  of  Figure  7  (Enlarged) 55,58 

9  Wingless  form  of  sugar  beet  root-louse  found  on  beets  dur- 

ing summer  (Enlarged) 55,58 

10  A  lady-beetle  which  feeds  upon  sugar  beet  root-lice  (En- 

larged)  59,  115,  132 

1 1  Antenna  of  wingless  louse  (Enlarged) 55,58 

12  Antenna  of  wingless  louse  (Enlarged) 55,  58 

1 3  Antenna  of  true  male  sugar  beet  root-louse,  Figure  1 6  (En- 

larged)  55,57 

14  A  true  bug,  Authocoris  melanocerus ,  which  feeds  on  lice  in 

gall  (Enlarged) 59,  132 

15  Larva  of  lady-beetle  (Figure   10),  which  also  feeds  on  lice 

while  on  beets  (Enlarged) 59,  115,  132 

16  True  male  sugar  beet  root-louse  (Much  enlarged.     Note 

minute  representation  of  actual  size  at  left  of  colored 
picture) 55,57 

17  Solitary  egg  laid  by  female  sugar  beet  root-louse  (Enlarged).55,  57 

18  True  female  sugar  beet  root-louse  (Much  enlarged.     Note 

minute  representation  of  actual  size  at  left  of  colored 
picture) ^ 55,  57 

Note:  Incase  of  enlargement,  a  natural  size  black  and 
white  outline  drawing  is  shown  beside  the  colored  picture.  Ex- 
ceptions to  this  plan  on  Plate  II  are  Figures  2,  8,  11,  12,  13 
and  17. 


12 


>^y.  /6  ^.  /7 


13 


PLATE  IV  page 

Fig.  1     Work  of  flea-beetles  on  a  beet  leaf 89, 91 

2  Adult  Banded  Flea-beetle,  Systena  taeniata  Say  (Enlarged)       92 

3  A  flesh-fly  parasite  of  grasshoppers,  Sarcophage  variacauda 

Coq.  (Enlarged) 105 

4  Maggot  of  Figure  3  (Enlarged) 1 05 

5  Adult  Potato  Flea-beetle,  Epitrix  cucumeris  Harr.    (En- 

larged)        93 

6  Adult   Three-spotted   Flea-beetle,    Disonycha   triangularis 

Say  (Enlarged) 93 

7  An  immature  female  Field  Cricket 109,  1 10 

8  Grasshopper  egg-pod 104 

9  Young  Two-lined  Hopper,  Melanojplus  bivittatus  Say  (En- 

larged)  100,  105 

10  Adult  female  Two-lined  Hopper 100,  104 

1 1  Outline  drawing  of  tip  of  female's  abdomen,  Two-lined 

Hopper,  showing  ovipositor 100,  104 

12  Adult  male  Differential  Hopper,  Melanoplus  differentialis 

Thos.,  yellow  phase 100 

1 3  Adult  male  Differential  Hopper,  black  phase 1 00 

14  Adult  Red-legged  Locust,  Melanoplus  femur-rubrum  De  G.  100 

1 5  Outline  drawing  of  last  segment  of  male's  abdomen,  adult 

Red-legged  Locust 1 00 

16  Hair  Worm.     A  parasite  of  grasshoppers  and  other  insects 

—somewhat  enlarged.     See  also  Figures   17  and   18, 
Pages  107  and  108 107,  108 

Note:  In  case  of  enlargements,  natural  size  outline 
drawings  are  shown  beside  the  colored  pictures.  Excep- 
tions on  Plate  IV  are  Figures  9  and  16. 


16 


PLATE  JZ 


CMPRESTON 


17 


PLATE  V  page 

Fig.   1     A  half  grown  grasshopper  with  Locust  Mites  attached  105, 106, 107 

2  Young  mite  (Enlarged) 106,  107 

3  Beet  leaf  with  young  Sugar  Beet  Webworm  at  "A" 67,  75 

4  Young  Sugar  Beet  Webworm  (Enlarged) 67,  75 

5  Portion  of  beet  leaf  with  Sugar  Beet  Webworm  moth  eggs 

(Slightly  enlarged) 67,  74 

6  Full  grown  Sugar  Beet  Webworm  (Enlarged) 67,  7 1 ,  75 

7  Sugar  Beet  Webworm  parasite,  Cremnops  vulgaris 77,  136 

8  Sugar  Beet  Webworm  cocoon 67,  75 

9  Pupa  of  Sugar  Beet  Webworm 67,  75 

10  Last  segment  of  Sugar  Beet  Webworm  pupa  (Enlarged) .  .67,  75 

1 1  Adult   Sugar  Beet  Webworm   moth,    Loxostege   sticticalis 

Linn 67,  68,  75,  85 

12  Puparium  of  figure  13   (Enlarged) 77 

13  A    two-winged   Tachina-fly    parasite   (Meteorus   loxostegei 

Vier.)  of  the  Sugar  Beet  Webworm  (Enlarged) 77 

14  A  Braconid  reared  from  a  Sugar  Beet  Webworm  (Enlarged) 

77,  136,  137 

15  Yellow-bear  Caterpillar * 86,  87 

16  Adult  Yellow-bear  Caterpillar,  Diacrisia  virginica  Fab 86,  87 

17  Adult  female  Locust-mite  (Trombedium  locustarum  Riley) 

and  eggs  (Enlarged) 106,  107 

18  Adult  male  Locust-mite  (Enlarged) 106,  107 

Note:  In  case  of  enlargement,  a  natural  size  black  and 
white  outline  drawing  is  shown  beside  the  colored  picture.  Ex- 
ceptions on  Plate  V  are  Figures  2,  3,  4  and  10. 


I') 


PLATE  VI  Page 

Fig.   1  Alfalfa  Webworm  (Enlarged) 83,  84 

2  Pupa  of  Alfalfa  Webworm 84,  85 

3  Last  Segment  of  Alfalfa  Webworm  pupa  (Enlarged) 84,  85 

4  Adult  Alfalfa  Webworm,  Loxostege  commixtalis  Walker  75,  84,  85 

5  Alfalfa  Looper 81,  83 

6  Cocoon  of  Alfalfa  Looper 81 ,  83 

7  Pupa  of  Alfalfa  Looper 81,  83 

8  Adult    Alfalfa    Looper,    Autographa    gramma    californica 

Speyer 81,83 

9  Itoplectis    atrocoxalis     Cress,     male.     An     Ichneumon-fly 

parasite  of  the  Alfalfa  Looper 83,  136 

10  Itopiectis    atrocoxalis    Cress,    female.     An    Ichneumon-fly 

parasite  of  the  Alfalfa  Looper 83,  136 

1 1  An  undetermined  Tachina-fly  parasite  of  the  Alfalfa  Web- 

worm (Enlarged) 85 

12  A  Robber-fly 78 

13  Syrphus-fly,  Syrphus  paulxillus  Will.  (Enlarged)   Its  larvae 

feed  on  Beet  Root-lice 59,  1 16 

14  A  two-winged  fly  (CMoropisca  glabra  Meign.)  whose  larvae 

are  found  among  Beet  Root-lice  (Enlarged) 59 

15  A  Solitary-wasp  (Odynerus  annuiatus  Say),  which  places 

web  worms  in  its  nest  as  food  for  its  young 77,  135 

16  A  full  grown  larva  of  the  Digger-wasp  (Fig.  1 8) ,  surrounded 

by  skin  of  a  cutworm 45,  134 

17  Cutworm  with  egg  of  the  Digger-wasp  (Fig.  18)  attached 

near  head 45,134 

18  A  Digger-wasp  (Sphex  luctuosa  Snw.)  carrying  a  cutworm 

into  its  burrow 44,  134 

Note:  In  case  of  enlargement,  a  natural  size  black 
and  white  outline  drawing  is  shown  beside  the  colored 
picture.  Exception  on  Plate  VI  is  Figure  3. 


20 


PLATE:  m. 


21 


PLATE  VII  Page 

Fig.    1     Larva  of  Alkali-beetle  (Enlarged) 89,  90 

2  Pupa  of  Alkali-beetle  (Enlarged) 89,  90 

3  Alkali-beetle  egg  (Enlarged) 89,  90 

4  Alkali-beetle  eggs  about  natural  size 89,  90 

5  Adult  Alkali-beetle,  Monoxia  puncticolis  Say    (Enlarged) . .  89,  90 

6  Adult  Western  Beet  Leaf-beetle,  Monoxia  consputa  Lee. 

(Enlarged) 90 

7  Variegated  Cutworm 47,  48 

8  Black  Blister-beetle,  Epicauta  jpennsylvamca  De  G.   (En- 

larged) . , 96, 98 

9  Ash-gray   Blister-beetle,   Macrobasis   unicolor    Kby.    (En- 

larged)    96,  98 

10  Spinach  Carrion-beetle,  Silpha  bituberosa  Lee.  (Enlarged) .  .94,  95 

1 1  Spinach  Carrion-beetle  larva  (Enlarged) 94,  95 

12  Winter  larva  of  a  Blister-beetle  (Enlarged) 96,  97 

13  The  final  larval  stage  of  a  Blister-beetle  (Enlarged) 96,  98 

14  Pupa  of  the  Lady-beetle,  Figure  10,  Plate  II,  Page  21  (En- 

larged)  59,  132 

1 5  Adult  Variegated  Cutworm,  Peridroma  margarltosa  Haw. .  .  47,  48 

Note:     In  case  of  enlargement,  a  natural  size  black  and 
white  outline  drawing  is  shown  beside  the  colored  picture. 


22 


PLA  TE  JZZ7 


23 


PLATE  VIII  Page 

Fig.  1     Sugar  beet  leaf  discolored  by  feeding  of  insects  shown  in 

Figures  3  and  4 1 28 

2  Eggs  of  Green  Peach-aphis,  Myzus  persicae  Sulz.    (En- 

larged)  116,  117 

3  Nymph  of  Figure  4  (Enlarged) 128 

4  Adult  Leaf-hopper,  Eutettix  strobi  Fitch  (Enlarged) 128 

5  Sugar  beet  leaf  affected  by  Curly-top 123,  124 

6  Nymph  of  Figure  7  (Enlarged) 123,  126 

7  Sugar  beet  Leaf-hopper    (Eutettix   tenella   Baker),   which 

carries  the  disease  known  as  Curly-top  (Enlarged) .  .  1 23 ,  1 26 

8  Clover    Leaf-hopper,    Agallia    sanguinolenta    Prov.    (En- 

larged)   126,  127 

9  Wingless  Green  Peach-aphis  (Enlarged) 116 

10  Winged  Green  Peach-aphis  (Enlarged) 116 

1 1  Nymph  of  False  Chinch  Bug  (Enlarged) 1 19,  1 2 1 

12  Adult  False  Chinch  Bug,  Nysius  ericae  Schill. (Enlarged) .  1 19,  121 

Note:  In  case  of  enlargement,  a  natural  size  black  and 
white  outline  drawing  is  shown  beside  the  colored  picture.  The 
only  exception  to  this  on  Plate  VIII  is  Figure  2. 


24 


25 


PLATE  IX 

Beneficial  Insects  Page 

Fig.   1     Larva  of  Fiery  Hunter,  shown  in  Figure  2 130 

2  Fiery  Hunter,  Calosoma  calidum  Fab 54,  130 

3  A  common  Ground  Beetle 130 

4  A  cutworm  killed  by  Chalcis-fly  parasites 44,  137 

5  Larva  of  Tiger-beetle 131 

6  Adult  Tiger-beetle,  Cicindela  vulgar  is  Say 131,132 

7  Adult  Tiger-beetle,  Cicindela  purpurea  Oliv 131,  132 

8  Eggs  of  bug  shown  in  Figures  1 2  and  13 133 

9  An  egg  shown  in  Figure  8,  much  enlarged 133 

10  A  half  grown  nymph  of  the  bug  shown  in  Figure  12 133 

1 1  A  newly  hatched  nymph  of  the  bug  shown  in  Figure  1 2  (En- 

larged)   133 

12  A  predacious  bug,  Perillus  daudus,  yellow  phase 133 

13  A  predacious  bug,  Perillus  daudus,  red  phase 133 

14  Eggs  of  Lady-beetle  shown  in  Figure  15 132 

15  Adult    Lady-beetle,   Hippodamia    convergent    Guer    (En- 

larged)  115,  132 

16  Eggs  of  Lace-winged  Fly,  shown  in  Figure  19 133 

17  Cocoon  made  by  larva  (Figure  18)  of  Lace-winged  Fly, 

shown  in  Figure  19. 133,  134 

18  Larva  of  Lace-winged  Fly,  shown  in  Figure   19.     Often 

called  "Aphis-lion"  (Enlarged) 116,  133,  134 

19  Adult  Lace-winged  Fly.     Commonly  called  "Golden-eye" 

(Enlarged) 1 16,  133 

20  Larva  of  Ground  Beetle,  Figure  22  (Enlarged).     It  feeds 

on  grasshopper  eggs 106,  130 

21  Pupa  of  Ground  Beetle,  shown  in  Figure  22  (Enlarged) .  106,  130 

22  Adult  Ground  Beetle,  Amara  obesa  Say  (Enlarged) 106,  130 

23  Larva  of  Lady-beetle,  Figure  15  (Enlarged) 1 15,  132 

24  Pupa  of  Lady-beetle,  Figure  1 5  (Enlarged) 132 

Note:  In  case  of  enlargement,  a  natural  size  black  and 
white  outline  drawing  is  shown  beside  the  colored  picture.  Ex- 
ceptions on  Plate  IX  are  Figures  9,  11,  and  22. 


26 


PLATE  IT 


27 


CHAPTER  I 


INSECTS  IN  GENERAL 

Knowledge  of  the  structure,  development,  classification  and  methods 
of  control  of  insects  in  general  will  enable  the  reader  to  understand  better 
the  text  dealing  with  any  individual  insect.  The  purpose  of  the  brief 
discussion  in  this  chapter  is  to  give  that  preliminary  setting. 

STRUCTURE 

All  adult  insects  have  the  head,  thorax  (chest)  and  abdomen  more 
or  less  distinctly  separated.  Attached  to  the  front  of  the  head  are  two 
antennae,  or  feelers,  as  they  are  popularly  called.  The  mouth  parts  are 
formed  for  biting  or  sucking.  Those  of  biting  insects,  such  as  grasshop- 
pers, flea-beetles  and  alkali-beetles,  consist  of  hard,  sharp-edged  jaws. 
Sucking  insects,  such  as  the  false  chinch  bug,  plant-lice  and  others,  have 
the  mouth  parts  prolonged  into  a  long,  straight  beak  which  is  often  jointed. 
In  the  case  of  moths  and  butterflies  the  larvae  have  biting  mouth  parts 
while  those  of  the  adults  are  in  the  form  of  a  slender  proboscis,  which  is 
carried  coiled  beneath  the  head.  In  the  adult  stage  there  are  always 
three  pairs  of  legs  attached  to  the  thorax.  These  three  pairs  of  legs  are 
present  in  the  immature  stages  of  beetles,  the  true  bugs,  moths  and  but- 
terflies, while  the  young  of  the  two-winged  flies,  bees,  wasps  and  others 
are  legless.  Aside  from  the  true  legs,  which  are  located  near  the  head, 
caterpillars  have  from  two  to  twelve  fleshy  leglike  organs  on  the  ab- 
domen. These  are  called  prolegs  or  props.  These  prolegs  are  furnished 
with  both  hooks  and  suction  pads.  Most  adult  insects  have  one  or  two 
pairs  of  wings,  which  are  also  attached  to  the  chest. 

Insects  breathe  through  small  openings  or  spiracles  in  the  abdomen. 
From  these  openings  the  air  is  carried  through  tubes  called  tracheae,  lead- 
ing to  the  various  parts  of  the  body. 

Spiders,  ticks  and  mites  are  not  insects,  but  belong  to  a  group  of 
invertebrate  animals  which  have  the  head,  thorax  and  abdomen  closely 
united  and  possess  four  pairs  of  legs  in  the  adult  stage;  however,  in  the 
immature  stages  some  have  but  three  pairs. 

DEVELOPMENT 

In  the  course  of  their  development  most  insects  undergo  remarkable 
changes  in  form.  These  changes  constitute  what  is  known  as  insect 
metamorphosis. 

One  order  of  insects  develops  without  change  in  form  or  without 
metamorphosis.  The  young  when  hatched  from  the  egg  have  the  same 
form  as  the  adult.  A  common  representative  of  this  group  is  often  seen 
floating  in  dense  masses  on  water.  Another  is  sometimes  seen  hopping 
about  on  the  snow  during  warm  days  in  early  spring  in  northern  latitudes. 

The  insects  belonging  to  another  class  undergo  considerable  change 
in  form  during  their  development,  but  the  young  resemble  the  adults 

29 


Insects  in  General 

quite  closely;  therefore  the  metamorphosis  is  said  to  be  incomplete. 
Grasshoppers,  plant-lice  and  the  true  bugs  are  common  examples  of  this 
class.  The  young  of  these  insects  are  called  nymphs. 

The  early  forms  of  many  insects,  like  the  butterflies,  moths,  flies, 
bees  and  beetles,  differ  so  from  the  adults  that  there  is  no  resemblance 
whatever  between  the  two.  These  insects  pass  through  at  least  four 
stages,  the  egg,  larva,  pupa  and  adult,  each  differing  in  form  from  the 
other.  For  this  reason  their  metamorphosis  is  said  to  be  complete. 

The  Egg 

The  egg  is  the  first  stage  in  the  development  of  any  insect.  The  eggs 
of  some  insects,  like  the  plant-lice,  remain  in  the  abdomen  of  the  mother 
until  the  young  are  fully  developed  and  hatched.  Insect  eggs  vary 
greatly  in  form,  as  can  be  seen  by  referring  to  the  figures  given  in  the 
Colored  Plates. 

The  Larva 

The  larva  is  the  form  of  an  insect  immediately  following  the  egg.  It 
is  then  in  the  stage  of  growth,  and  many  of  our  common  insects  damage 
crops  more  severely  during  this  period  of  their  lives  than  at  any  other 
time.  Larvae  differ  greatly  in  form  in  the  different  orders.  The  larvae 
of  moths  and  butterflies  are  called  caterpillars;  those  of  flies  are  called 
maggots;  those  of  some  beetles  are  called  grubs  and  others  worms. 
Caterpillars  are  often  called  worms  also.  The  legless  larvae  of  bees, 
wasps  and  related  insects  are  sometimes  called  grubs. 

The  Pupa 

The  pupa  is  the  third  or  resting  stage.  The  larva  becomes  a  pupa 
when  it  has  completed  its  growth.  In  this  stage  the  insect  has  very  little 
or  no  power  of  movement,  being  unable  to  do  more  than  wriggle  the  tip 
of  the  abdomen  at  most.  The  pupa  of  a  butterfly  or  moth  is  called  a 
chrysalis;  the  hardened  larval  skin  within  which  the  pupa  of  some  two- 
winged  flies  is  formed  is  termed  a  puparium. 
The  Adult 

The  adult  is  the  fourth  and  final  stage  in  an  insect's  development. 
No  further  growth  takes  place  after  this  stage  is  reached.  Only  enough 
food  is  taken  by  the  adult  to  sustain  life;  in  fact  some  adults  do  not  feed 
at  all,  their  mouth  parts  having  been  lost  through  disuse.-  The  prin- 
ciple function  of  the  adult  is  that  of  reproduction. 

The  Integument 

The  skin  or  integument  of  an  insect  is  composed  of  a  tough,  horny 
substance  called  chitin  (pronounced  ki-tin).  At  certain  periods  dur- 
ing the  larval  stage  this  becomes  so  hard  that  it  cannot  stretch  and  soon 
becomes  too  small  for  the  growing  insect.  In  the  meantime  a  new  skin 
is  forming  underneath  the  old  one,  which  splits  open.  The  insect  then 
frees  itself  from  its  old  coat.  This  process  is  called  molting.  The  new 
skin  is  at  first  soft  and  stretches  to  accommodate  the  increasing  size  of  the 
insect.  Soon,  however,  it  becomes  hardened  and  must  in  turn  be  cast  off 
I  nus,  in  the  course  of  their  development  insects  shed  their  skins  several 
times.  After  reaching  the  adult  stage  molting  ceases  and  all  growth 
stops. 

30 


Insects  in  General 
CLASSIFICATION 

The  insects  that  injure  agricultural  crops  can  be  roughly  grouped 
into  two  classes :  those  that  feed  upon  the  roots  and  underground  parts  of 
plants,  or  "root  feeders;"  and  those  that  feed  upon  the  leaves  and  other 
parts  of  plants  above  the  ground,  or  "leaf  feeders." 

Each  of  these  groups  can  in  turn  be  divided  into  two  other  classes : 
insects  which  bite  their  food,  or  "biting  insects,"  and  those  which  suck 
their  food,  or  "sucking  insects." 

Both  classifications  are  most  important  from  the  viewpoint  of  insect 
control . 

The  mouth  parts  of  the  biting  insects  consist  of  an  upper  and  lower 
lip  between  which  are  two  pairs  of  jaws  with  which  portions  of  the  food 
plant  are  bitten  out  and  masticated.  Attached  to  these  jaws  are  slender, 
jointed  organs  used  in  guiding  the  food  to  the  mouth  or  as  sense  organs. 

The  mouth  parts  of  sucking  insects  are  modified  into  a  long,  jointed 
tube  or  beak  and  several  hair-like  bristles  which  are  enclosed  within  it.  In 
feeding,  the  beak  is  placed  against  the  surface  of  the  plant  while  the 
bristles  or  piercing  organs  are  forced  into  the  tissue.  The  plant  juice  is 
then  sucked  up  through  them  by  a  pumping  motion  of  the  mouth. 

METHODS  OF  CONTROL 

There  are  two  general  methods  of  insect  control,  the  cultural  or 
natural  method,  and  the  artificial  method. 

The  natural  method  consists  of  handling  the  soil  or  the  crop  in 
such  a  way  as  to  prevent  or  reduce  insect  injury,  and  in  fighting  injurious 
insects  with  their  natural  enemies. 

The  artificial  method  consists  of  the  application  of  any  substance 
to  a  crop  for  the  purpose  of  killing  attacking  insects  or  making  the  plants 
so  distasteful  to  them  that  they  will  not  feed  upon  them. 

Natural  Methods  of  Control 

Application  of  the  natural  methods  of  control  depends  largely  upon 
the  habits  and  life  history  of  the  insect  to  be  controlled.  For  example, 
in  the  case  of  the  grasshopper  we  know  that  its  egg  stage  is  passed  in  the 
ground  during  the  fall  and  winter.  Fall  plowing,  harrowing  and  discing 
will  kill  the  grasshopper  in  the  egg  stage. 

Crop  Rotation 

Crop  rotation  is  one  of  the  principal  factors  in  insect  control.  Many 
insects  feed  upon  only  one  crop  or  those  closely  related  botanically. 
It  is  evident,  therefore,  that  if  the  same  crop  is  planted  on  a  field  for 
several  years  in  succession  the  insects  attacking  it  are  likely  to  accumu- 
late in  and  about  it  until  serious  damage  results.  The  length  of  rotation 
necessary  to  insure  against  injury  by  an  insect  or  other  crop  pest,  depends 
upon  the  pest  in  question.  For  example,  the  corn  root  worm  can  be  con- 
trolled by  alternating  corn  with  any  other  crop ;  while  white  grubs  and 
wireworms  require  a  three  or  four  year  rotation;  and  the  sugar  beet 
nematode  a  much  longer  rotation. 

Other  insects  deposit  their  eggs  upon  certain  crops  or  in  the  soil 
where  these  crops  are  growing  or  have  grown.  Loss  can  be  avoided  by 
following  such  crops  with  others  which  are  not  attacked  by  this  class 
of  insect. 

31 


Insects  in  General 

Plowing 

Many  insects  pass  certain  tender  stages  of  their  development  in 
the  ground  or  on  plants  in  the  fields.  Plowing  infested  fields  at  the  pro- 
per time  will  do  much  toward  destroying  such  insects. 

Late  Planting 

Injury  can  sometimes  be  prevented  by  timing  the  planting  of  crops 
so  that  they  will  not  come  up  until  danger  of  infestation  is  passed. 

Burning 

Many  insects  spend  the  winter  in  hibernation  beneath  the  trash  or 
crop  refuse  on  and  about  fields.  If  this  waste  matter,  dead  weeds  and 
grass  about  fence  rows  and  ditch  banks  is  burned  during  the  fall  or  winter, 
many  insects  will  be  destroyed  which  would  otherwise  damage  crops  the 
following  spring. 

Clean  Culture 

Nearly  all  injurious  insects  fed  upon  wild  plants  before  the  land 
was  broken  up  and  planted  to  crops.  If  weeds  are  allowed  to  grow  in 
a  crop  or  about  the  fields,  ditch  banks,  fences  or  roadsides,  they  attract 
these  insects  to  the  vicinity.  After  the  wild  food  plants  have  been 
destroyed,  the  insects  turn  their  attention  to  crops  and  much  damage 
results.  Clean  cultivation  is  always  profitable  from  the  standpoint  of 
insect  control  as  well  as  for  other  reasons. 

Artificial  Method  of  Control — Insecticides 

What  substance  to  use  and  how  to  use  it  in  artificial  control  depends 
upon  whether  the  insects  are  biting  or  sucking  insects.  There  are 
two  general  classes  of  insecticides,  those  which  kill  after  they  are  eaten 
(stomach  poisons),  and  those  which  kill  by  coming  in  contact  with  the 
insects  (contact  poisons).  The  first  is  used  against  insects  which  bite 
their  food,  and  the  second  against  those  which  suck  it. 

Control  of  Biting  Insects 

In  the  control  of  most  biting  insects  poisonous  substances  such  as 
Paris  green  and  arsenate  of  lead  are  used.  These  are  applied  either  as  a 
spray  mixed  with  water  or  dry.  In  the  latter  case  the  poison  is  mixed 
with  low  grade  flour,  air  slaked  lime  or  some  other  fine  powder  and  dusted 
onto  the  crop.  The  poisons'are  often  mixed  with  some  substance  which 
the  insects  will  eat,  and  this  poisoned  bait,  as  it  is  called,  is  scattered 
over  infested  fields. 

In  the  control  of  some  biting  insects  it  is  necessary  to  kill  them  while 
in  the  egg  stage.  This  is  done  by  spraying  with  oils  which  can  be  mixed 
with  water  or  with  lime-sulphur  wash  (See  page  115).  These  oils  are 
petroleum  products  rendered  soluble  by  the  addition  of  vegetable  oils 
and  are  known  by  the  trade  name  of  "miscible  oils." 

Many  biting  insects  devour  the  entire  leaf  in  feeding,  while  others 
feed  on  the  under  side  of  the  leaves  only,  eating  all  but  the  upper  surface. 
In  applying  stomach  poisons  it  is  very  essential  that  the  location  of  the 
insects  while  feeding  be  known.  If  they  feed  on  the  under  side  of  the 
leaves  the  sprayer  must  be  adjusted  so  that  the  poison  is  applied  to  the 
lower  surface. 

32 


Insects  in  General 


Sprayers 


Sometimes  arsenical  poisons  burn  the  leaves  of  plants,  especially 
if  the  application  is  heavy.  This  is  due  to  free  arsenious  acid  in  the 
material  used.  The  addition  of  a  little  quick  lime  to  the  water  in  which 
the  poison  is  mixed  will  prevent  this  burning.  When  lime  has  been 
added  the  solution  must  be  carefully  strained  to  remove  particles  of  lime 
which  would  otherwise  clog  the  nozzles. 

Control  of  Sucking  Insects — Contact  Poisons 

In  the  control  of  sucking  insects  the  contact  poisons  kill  the  insects 
either  by  corroding  their  bodies  or  by  clogging  their  spiracles,  thus 
causing  strangulation.  Black-leaf  40  (See  page  114),  kerosene  emulsion 
(See  page  1 14),  the  so-called  insect  powders  and  soluble  oils  are  standard 
remedies  for  sucking  insects.  As  the  name  implies,  these  substances 
must  come  in  actual  contact  with  the  insect  to  kill  it. 

Repellents 

A  repellent  is  any  substance  the  presence  of  which  on  plants  makes 
them  so  distasteful  to  insects  that  they  will  not  feed  upon  them.  Mix- 
tures containing  tobacco  preparations  or  soap,  especially  whale  oil  soap, 
are  effective  as  repellents. 

SPRAYERS 
A.     TRACTION  SPRAYER 

For  field  use  any  one  of  the  many  makes  of  traction  sprayers  (Fig. 
I,  Page  33)  is  recommended. 


Fig.  1.     A  Good  Type  of  Traction   Sprayer  for  Field  Use 
33 


Sprayers 

Such  a  machine  should  embody  the  following  features : 

A.  A  tank  of  sufficient  capacity  to  permit  of  spraying  large  fields 
without  having  to  fill  it  in  the  center  of  the  field.     A  tank  holding  50 
gallons  is  large  enough  for  practical  purposes. 

B.  A  revolving  agitator  within  the  tank  to  keep  the  poison  in 
suspension. 

C.  A  force  pump  to  maintain  a  pressure  at  the  nozzles  in  order  to 
produce  a  fine  mist-like  spray.     This  pump  should  be  driven  by  the 
wheels  of  the  sprayer. 

D.  A  pressure  gauge. 

E.  A  large  air  chamber. 

F.  An  adjustable  safety  valve  to  prevent  bursting  the  rubber  hose 
connections. 

G.  An  adjustment  whereby  the  machine  can  be  adapted  to  variable 
distances  between  rows  without  changing  piping,  hose  connections  or 
nozzles. 

A  means  of  adjusting  the  wheels  to  varying  widths  of  rows. 

CARE  OF  SPRAYER 
Remove  Rust  Scales 

There  are  certain  soluble  acids  in  Paris  green  which  act  upon  the  iron 
parts  of  the  sprayers,  especially  the  iron  piping.  This  action  produces 
large  quantities  of  rust  which  falls  away  from  the  pipe  in  scales.  These 
scales  will  clog  the  nozzles  unless  the  piping  and  other  metal  parts  are 
thoroughly  cleaned. 

Remove  Dry  Paris  Green 

There  is  always  some  Paris  green  left  in  the  piping,  tank  and  nozzles. 
This  is  apt  to  cause  the  same  trouble  when  you  start  the  sprayer  as  the 
rust  scale  mentioned.  The  barrel,  or  whatever  kind  of  tank  there  is  on 
your  machine,  should  be  thoroughly  cleaned. 

Repair  Hose  Connections 

Be  sure  that  all  hose  connections  are  in  good  repair. 
Clean  Nozzles 

Often  times  the  nozzles  become  clogged  with  dry  Paris  green.     There- 
fore all  nozzles  should  be  taken  apart  and  thoroughly  cleaned. 
Examine  Pump 

The  pump  is  one  of  the  most  important  parts  of  a  sprayer.  Too 
much  pains  cannot  be  taken  in  seeing  that  the  pump  is  in  perfect  con- 
dition. Remember  that  the  pump  will  not  work  properly  if  not  properly 
packed. 

Examine  Valves 

Next  to  the  packing,  the  valves  are  most  important.  A  steady 
pressure  cannot  be  maintained  if  the  valves  are  not  in  perfect  condition. 

34 


Sprayers 
Clean  Relief  Valve 

The  relief  valve  which  regulates  the  pressure  should  be  examined, 
since,  if  this  fails  to  work,  the  hose  connections  are  very  apt  to  be  blown 
off. 

Neckyoke  and  Eveners 

Most  beets  are  planted  18  or  20  inches  apart  or  16  and  24  inches. 
In  either  case  three  rows  of  beets  should  be  between  the  wheels  and  the 
wheels  60  inches  apart.  The  eveners  and  neckyoke  should  be  60  inches 
long,  so  that  the  horses  walk  in  front  of  the  wheels.  Less  damage  will 
be  done  to  the  crop  from  broken  leaves  and  crushed  crowns  if  your 
machine  is  equipped  in  this  way. 

Setting  the  Nozzles 

The  nozzles  should  be  so  placed  as  to  make  it  possible  to  spray  thor- 
oughly all  surface  between  the  end  nozzles.  There  are  so  many  styles  of 
nozzle  equipments  and  frames  that  it  would  require  too  much  space  to 
explain  in  detail  the  setting  of  all.  Let  it  be  sufficient  to  say  that  four 
single  nozzles  should  not  cover  more  than  5  rows  of  beets  and  6  single 
nozzles  7  rows.  If  the  double  nozzles  are  used,  4  pairs  will  cover  8  rows 
and  6  pairs  12  rows.  In  spraying  very  small  beets  the  nozzles  should 
be  placed  directly  over  the  rows. 

Testing  the  Pump 

Before  attempting  to  do  any  spraying,  test  the  spray  pump  thor- 
oughly. The  pressure  regulates  the  kind  of  spray  your  machine  throws 
(fine  or  coarse),  also  the  amount  of  water  applied  to  an  acre  of  ground. 
Eighty  pounds  pressure  produces  the  fine  mist-like  spray  required 
for  best  results. 

Test  Your  Sprayer 

It  is  the  poison  applied  to  an  acre  of  beets  and  not  the  water  which 
kills  the  worms.  Quick  and  satisfactory  results  are  secured  by  the  use 
of  4  pounds  of  Paris  green  per  acre.  Unless  you  know  how  much  water 
your  sprayer  applies  to-  an  acre,  you  cannot  know  how  much  poison  to 
use  in  a  tank  of  water.  For  example,  if  a  sprayer  equipped  with  4  double 
nozzles  and  producing  a  pressure  of  80  pounds  will  cover  an  acre  with  50 
gallons  of  water,  you  should  mix  4  pounds  of  Paris  green  with  50  gallons 
of  water.  If  the  pressure  falls  very  much  below  80  pounds,  less  water 
will  be  applied  to  an  acre  and  more  Paris  green  will  have  to  be  added  to  a 
50-gallon  tank  of  water. 

To  test  your  sprayer  fill  the  tank  with  water,  put  the  pump  in  gear, 
then  drive  along  the  road  and  measure  the  distance  traveled  in  discharg- 
ing all  of  the  water  through  the  nozzles.  Multiply  this  distance,  meas- 
ured in  feet,  by  the  width  of  the  number  of  beet  rows  you  spray;  say  5 
twenty-inch  rows  or  8.3  feet,  and  divide  this  by  43,560,  which  is  the 
number  of  square  feet  in  an  acre.  This  will  give  you  the  part  of  an  acre 
you  spray  with  one  tank  of  water.  Many  failures  in  spraying  are  due 
to  using  too  little  poison,  and  much  loss  in  money  results  from  using  too 
much.  Avoid  this  by  testing  your  machine.  From  the  above  you  can 
determine  the  amount  of  Paris  green  to  use  with  a  tank  of  water  to 
apply  the  4  pounds  per  acre. 

35 


Sprayers 


KNAPSACK  SPRAYER 


For  use  in  gardens  or 
for  spraying  berry 
bushes  and  ornamental 
shrubs,  the  knapsack 
sprayer  (Fig.  2,  Page 
36)  is  very  convenient. 
This  sprayer  can  be 
placed  on  the  ground  or 
carried  as  shown  in  the 
figure.  Where  the  gar- 
den or  the  number  of 
plants  to  be  sprayed  is 
small  this  sprayer  is  not 
so  well  adapted  to  the 
work  as  the  hand 
sprayer. 


Fig.  2.     Knapsack  Sprayer 


HAND  SPRAYER 

The  hand  sprayer  (Fig. 
3,  Page  36)  is  suitable  for 
spraying  house  plants,  or  a 
very  small  fruit  or  vegeta- 
ble garden.  It  can  also  be 
used  to  apply  repellents  to 
live  stock.  Where  one  has 
only  occasional  use  for  a 
sprayer  to  spray  a  few 
plants  this  type  is  recom- 
mended because  of  its  small 
cost. 


Pig.   3.     Hand   Sprayer 


36 


Sprayers  Paris  Green 

The  accompanying  picture  (Fig.  3-a)  illustrates  a  home-made  spray- 
er, costing  approximately  $25.00.  This  machine  was  successfully  used 
during  the  1919  growing  season  in  the  Fort  Collins,  Colorado  district. 
Any  hand-power  spray  pump  may  be  used. 

A  HOME-MADE  SPRAYER 


Fig.   3-a.     A  Home-made  Sprayer 


CAUTION 

Since  Paris  green  is  a  poison,  due  care  should  be  exercised  in 
handling  it. 

Be  careful  not  to  get  Paris  green  on  the  hands,  face,  or  other 
parts  of  the  body,  or  to  rub  the  face  or  body  with  the  hands  if  any 
of  the  green  should  get  on  them.  The  safest  plan  is  to  wear  gloves. 

The  poison  is  absorbed  into  the  pores  of  the  skin  and  causes 
a  severe  rash  or  breaking  out.  This  absorption  is  more  rapid 
when  one  is  perspiring. 

Inhaling  the  dry  poison  may  cause  local  poisoning  of  the 
nasal  passages. 

Long  continued  handling  of  Paris  green  with  bare  hands  may 
result  in  systemic  poisoning  which  is  accompanied  by  typical 
internal  arsenical  poisoning  symptoms. 

The  average  person  will  become  poisoned  locally  only  after 
long  and  continuous  contact  with  Paris  green,  but  some  individ- 
uals are  much  more  susceptible  than  others.  This  susceptibility 
cannot  be  determined  beforehand,  hence  the  increased  need  for 
caution. 

In  measuring  Paris  green  use  a  long  handled  dipper. 

Always  use  a  wooden  paddle  for  mixing  it. 

Destroy  all  cans  or  paper  containers  in  which  Paris  green  is 
received,  after  emptying  them.  Children  may  be  poisoned  by 
playing  with  them. 

37 


Root  Feeders  Cutworms 

CHAPTER  II 


ROOT  FEEDERS 

Taken  as  a  class,  those  insects  which  inhabit  the  soil  and  feed  upon 
the  roots  and  other  underground  parts  of  plants  are  among  the  worst 
enemies  of  field,  orchard  and  garden  crops. 

Living  and  feeding,  as  they  do,  below  the  surface  of  the  ground  the 
greater  part  of  their  lives,  the  root  feeders  are  seldom  observed  at  work  in 
the  field. 

The  effect  of  injury  by  root  feeders  upon  the  leaves  and  other  visible 
'parts  of  plants  is  often  attributed  to  many  causes  but  the  right  one,  and  its 
association  with  the  insect  is  often  not  suspected  until  much  damage  has 
been  done,  if  at  all. 

Their  subterranean  habits,  together  with  '  he  rapidity  with  which  some 
forms  multiply,  and  the  ease  with  which  others  are  disseminated  over 
large  areas,  make  them,  with  few  exceptions,  extremely  difficult  to 
control. 

Furthermore,  the  study  of  the  habits,  life  history  and  control  of  many 
root  feeders  is  attended  by  peculiar  difficulties,  because  of  which  our  knowl- 
edge of  them  is  often  so  meager  that  we  are  unable  to  apply  effective  means 
of  control  when  some  insect  of  this  class  suddenly  appears  in  damaging 
numbers  in  our  fields. 

Probably  the  best  known  and  most  destructive  root  feeders  are  the 
cutworms,  whi  e  grubs,  wireworms,  corn  root-worms,  the  corn  root-louse 
and  the  sugar  beet  root-louse.  To  this  may  be  added  the  sugar  beet  nema- 
tode  and  other  closely  related  eelworms. 

A.    BITING  ROOT  FEEDERS 

(Cutworms,  White  Grubs,  Wireworms) 

1.    CUTWORMS 

The  name  "cutworm"  is  applied  in  a  general  way  to  all  of  the  hair- 
less larvae  (caterpillars)  of  a  group  of  moths  or  millers  called  "owlet 
moths,"  from  the  fact  that  they  fly  mostly  at  night  and  have  eyes  that 
shine  in  the  dark. 

Probably  no  other  insects  are  more  dreaded  in  those  sections  where 
they  cause  large  annual  crop  losses,  than  are  the  various  cutworms. 
Like  the  evil  gnomes  of  old,  who  sallied  forth  on  moonless  nights  to 
wreak  vengeance  upon  some  hapless  wayfarer,  the  cutworms  come  forth 
from  hiding,  and,  under  cover  of  darkness,  despoil  the  farmers'  crops; 
or,  like  the  "sappers"  of  an  invading  army,  these  invaders  of  our  fields 
tunnel  from  plant  to  plant,  leaving  a  trail  of  death  and  destruction  in 
their  wake. 

NATURE  OF  INJURY 

If,  in  walking  through  a  beet  field,  dead  and  wilted  plants  are  seen;  if 
stools  of  grain  in  grain  fields  are  dying  or  the  stand  is  becoming  thin;  or 

38 


Cutworms 

if  alfalfa  starts  very  slowly  or  makes  an  indifferent  growth  in  the  spring, 
the  fields  should  be  examined  for  cutworms. 

If  cutworms  are  causing  the  injury  the  dead  and  wilted  beets  or  dying 
stools  of  grain  will  be  found  cut  off  at  the  surface  of  the  ground,  or  just 
below  it.  Should  these  plants  still  be  attached  to  their  roots,  there  being 
no  evidence  of  their  having  been  partially  gnawed  off,  cutworms  are  not 
responsible  for  the  plants  dying.  In  case  the  plants  have  been  killed  for 
some  time  the  dead  and  dried  leaves  may  have  been  blown  away,  leaving 
the  ground  bare.  In  this  case  the  stubs  of  the  plants  will  be  found  if  the 
soil  is  removed  to  a  depth  of  one-half  inch  or  so. 

When  the  slowness  in  starting  or  indifferent  growth  of  alfalfa  is  due 
to  cutworms  many  new  shoots  will  be  found  wilted  and  dead.  These 
will  be  gnawed  off  near  the  crown  of  the  plant.  As  in  the  case  of  beets 
and  grain,  shoots  that  are  not  at  least  partially  gnawed  off  have  not  been 
killed  by 'cutworms. 

While  the  foregoing  is  usually  sufficient  evidence  that  cutworms  are 
or  have  been  injuring  a  crop,  yet  the  real  proof  is  in  finding  the  worms. 

WHERE  TO  LOOK  FOR  THE  WORMS 

Most  cutworms,  like  the  moths  which  produce  them,  are  nocturnal 
in  habit.  They  lie  hidden  beneath  trash  or  just  below  the  surface  of 
the  soil  during  the  day,  coming  forth  toward  dusk  and  during  the  night 
to  feed.  When  very  numerous  and  during  cloudy,  damp  days,  they 
sometimes  move  about  quite  freely  in  the  early  part  of  the  day. 

In  infested  fields  the  worms  will  usually  be  found  buried  in  the  soil 
near  some  plant  which  has  been  recently  cut  off.  In  alfalfa  they  will  be 
found  buried  near  the  crowns  of  the  plants  or  under  the  trash  scattered 
over  the  field.  Many  times  they  accumulate  under  boards  and  other 
objects  lying  on  the  surface  of  the  ground.  Careful  watch  should  be 
kept  for  worms  before  planting  as  damage  can  best  be  avoided  by  de- 
stroying them  before  the  crop  is  sown. 

METHODS  OF  CONTROL 

Poisoned  Bait;  Kansas  Mixture 

The  best  known  method  of  killing  cutworms  is  the  use  of  poisoned 
bait.  A  poisoned  bran  mash  known  as  Kansas  Mixture  seems  to  give 
the  best  results.  The  formula  for  use  against  cutworms  is  as  follows : 

20  Ibs.  bran  or  shorts; 

1  Ib.  Paris  green; 

2  qts.  molasses  (any  cheap  grade  or  beet  molasses) ; 

2  lemons  or  oranges  (lemons  preferred) ; 

3  gals,   water. 

How  to  Make  Kansas  Mixture 

Thoroughly  mix  the  bran  or  shorts  and  the  Paris  green  dry.  Chop 
the  lemons  or  oranges,  rind  included,  very  fine.  If  a  food  chopper  is 
available,  use  this.  Add  the  molasses  and  chopped  fruit  to  about  one- 
half  of  the  water  and  stir  until  the  molasses  is  dissolved.  Add  this 
mixture  to  the  bran  and  Paris  green  and  mix  evenly.  The  rest  of  the 
water  should  then  be  added  a  little  at  a  time,  stirring  the  mixture  while 
doing  so,  and  until  the  whole  mass  is  evenly  moistened.  When  this 

39 


Cutworms 

has  been  done  the  bran  should  be  just  moist  enough  to  stick  together, 
but  not  so  wet  that  it  will  not  crumble  freely.  In  this  condition  it 
can  be  evenly  and  thinly  scattered  over  the  field  to  be  treated. 

How  to  Apply  the  Bait 

The  poisoned  bait  should  be  scattered  broadcast  over  the  infested 
field.  This  can  be  done  by  hand,  care  being  taken  to  prevent  large  lumps 
from  being  left  in  the  field  unbroken.  If  the  bait  is  thinly  and  evenly 
scattered  there  is  no  danger  of  poultry  or  livestock  being  poisoned  by 
eating  it.  If  properly  scattered  a  mixture  made  of  20  pounds  of  bran 
will  cover  I\  acres. 

Time  to  Put  Out  the  Bait 

Since  the  cutworms,  as  a  rule,  do  not  begin  feeding  until  late  after- 
noon or  early  evening,  the  bait  should  not  be  spread  until  about  sun- 
down. If  spread  earlier  in  the  day,  especially  if  the  weather  is  hot  and 
dry,  the  bait  will  become  dried  out  before  the  worms  begin  feeding. 
In  this  case  the  results  are  apt  to  be  disappointing.  It  is  claimed  that 
cutworms  feed  much  more  freely  on  shorts  when  dried  out  than  on  bran.* 

Treating  Fields  Before  Planting 

Infested  fields  should  be  treated  with  poisoned  bait  before  plant- 
ing.    If  properly  applied  one  application  of  Kansas  Mixture  is  sufficient 
to  rid  a  field  of  cutworms.     After  being  treated  in  this  manner  a  field 
can  be  planted  with  safety. 
Other  Poisoned  Bait 

Freshly  cut  clover  or  alfalfa  thoroughly  sprayed  with  Paris  green 
and  water  (1  Ib.  Paris  green  to  25  gallons  water)  and  spread  over  infested 
fields  is  often  substituted  for  Kansas  Mixture.  It  is  very  doubtful  if 
this  is  as  satisfactory  as  the  poisoned  bran  mixture.  This  method 
should  be  avoided  because  of  the  danger  of  poisoning  live  stock. 

Rolling 

Rolling  is  sometimes  recommended  for  killing  cutworms.  How- 
ever, it  is  a  doubtful  method  and  one  which  is  very  apt  to  be  disappoint- 
ing in  its  results.  Unless  the  surface  of  the  field  is  very  smooth  and 
compact,  rolling  is  a  waste  of  time  for  this  purpose.  If  done  at  all  it 
must  be  done  at  night  when  the  worms  are  moving  on  the  surface.  Gen- 
erally speaking,  rolling  is  not  to  be  recommended. 

Discing 

Discing  is  even  less  effective  than  the  roller,  for  destroying  cut- 
worms, and  is  not  recommended. 
Plowing 

Deep  fall  plowing  will  often  give  good  results,  especially  if  the  soil 
is  thoroughly  disced  before  plowing  and  the  surface  well  worked  down 
afterward. 

Replowing  of  infested  fields  in  the  spring,  if  the  plowing  is  deep 
and  the  surface  thoroughly  worked  afterward,  has  given  good  results 
when  the  season  is  not  too  far  advanced  for  the  planting  of  early  matur- 
ing crops. 

"*  ™**  Provinces'"  Circular  N°'  *•  Department  of 

40 


Cutworms  Western  Army  Cutworm 

Late  Planting 

Late  planting  may  sometimes  be  resorted  to  as  a  means  of  prevent- 
ing loss  by  cutworms.  However,  before  resorting  to  this  means  the 
best  plan,  if  one  is  in  doubt  as  to  the  identity  of  the  particular  cutworm 
in  question,  is  to  send  some  of  the  worms  to  the  State  Entomologist, 
to  the  Experimental  Department  of  The  Great  Western  Sugar  Company, 
Longmont,  Colorado,  or  to  some  one  else  familiar  with  these  insects  and 
qualified  to  give  advice  regarding  them.  If  this  is  done  much  time  and 
many  dollars  may  be  saved.  Before  resorting  to  late  planting  read 
carefully  what  follows  about  the  different  species  of  cutworm,  especially 
the  Pale  Western  Cutworm. 

(a)     WESTERN  ARMY  CUTWORM 

(Figs.  1,  2,  3  and  4,  Plate  I,  Page  11) 

The  name  "western  army  cutworm"  has  been  applied  to  this  species 
because  under  favorable  conditions  it  becomes  very  numerous  and  at 
such  times  travels  en  masse  in  much  the  same  way  as  the  true  army  worms. 

It  is  also  often  called  the  "alfalfa  cutworm,"  because  of  its  prefer- 
ence for  this  crop.  In  Northern  Colorado  it  seldom  injures  crops  unless 
they  are  planted  on  recently  broken  alfalfa  land  or  in  fields  adjoining 
infested  alfalfa  fields. 

DESCRIPTION 
The  Worm 

Figure  1,  Plate  I,  Page  11  represents  a  full  grown  western  army 
cutworm,  natural  size.  This  worm  is  marked  with  various  shades  of 
brown  above,  while  the  lower  part  is  a  dirty  white.  There  are  usually 
several  dark  spots  on  each  segment  of  the  body.  Each  of  these  bears 
a  short,  stiff  bristle.  These  bristles  are  not  always  easily  seen  with  the 
naked  eye.  Some  individuals  are  much  darker  than  in  the  figure,  while 
others  are  lighter.  This  is  the  most  common  cutworm  in  alfalfa  fields. 

The  Pupa 

Shortly  after  the  cutworm  becomes  full  grown  it  burrows  into  the 
soil  to  a  depth  of  about  two  inches.  The  next  few  days  are  spent  in 
wriggling  and  twisting  about,  making  a  cosy  cell  in  the  soil. 

Rapid  changes  now  begin  to  take  place  in  the  worm.  It  gradually 
shortens  and  changes  from  its  original  color  to  a  dirty,  whitish  yellow. 
The  skin,  which  has  become  much  shrunken  and  wrinkled,  now  cracks 
open,  exposing  a  yellowish  brown  object  within.  A  few  more  twists 
and  turns  and  the  pupa  (Fig.  2,  Plate  I,  Page  11)  frees  itself  from  the 
skin  which  covered  the  worm. 

The  Moth 

The  change  from  worm  to  pupa  is  only  the  beginning.  During  the 
next  two  or  three  weeks  nature  is  at  work  within  the  brown  walls  of 
the  pupa  forming  a  body,  legs  and  wings  and  hundreds  of  feather-like 
scales  (Fig.  4,  Page  42)  to  cover  them.  When  all  is  complete,  our  ugly 
cutworm  has  taken  on  still  another  form.  The  brown  walls  of  the  pupa 
burst  open  and  after  much  pulling  and  straining  the  moth  emerges. 
At  each  side  of  its  body  hang  two  crumpled  objects.  As  we  watch  these 
they  begin  to  expand  and  lengthen.  In  a  very  short  time  they  have 

41 


Western  Army  Cutworm 

developed  into  delicately  colored  wings.     The  cutworm  has  now  reached 
the  fourth  or  perfect  stage,  the  moth. 

These  moths  (Fig.  3,  Plate  I,  Page  1 1)  are  easily  recognized  by  the 
light  stripe  on  the  forward  edge  of  the  fore  wing.  A  few  individuals 
lack  this  stripe,  the  fore  wing  being  colored  as  shown  in  Figure  4,  Plate 
I,  Page  11. 


Fig.     4.     Scales  from  Wing  of  Moth  of  Western  Army  Cutworm, 
highly  magnified 

LIFE  HISTORY 

Our  knowledge  of  the  life  history  of  the  western  army  cutworm  is 
incomplete.  However,  recent  investigations  conducted  by  Prof.  R.  A. 
Cooley,  Entomologist  of  the  Montana  Experiment  station,*  have  de- 
termined some  of  the  more  important  points. 

Prof.  Cooley  and  his  associates  draw  the  conclusion  that  the  west- 
ern army  cutworm  is  single  brooded  in  Montana.  This  is  probably 
true  of  Northern  Colorado  as  well. 

The  eggs  are  deposited,  so  far  as  is  known,  on  bare  ground,  on  clods 
of  earth,  stubble  and  dead  roots  on  the  surface  of  the  soil.  Each  female 
moth  is  capable  of  laying  several  hundred  whitish,  ribbed,  and  more 
or  less  globular  eggs  similar  to  those  which  are  shown  much  enlarged 
on  Plate  I,  Page  11,  Figures  11  and  12.  The  greater  part  of  the  egg 
laying  is  done  during  September  and  October. 

The  eggs  hatch  in  about  ten  days  under  ordinary  conditions,  but  a 
longer  time  is  required  if  the  weather  is  cool  or  the  season  advanced 

*  "Observations  of  the  Life  History  of  the  Army  Cutworm."  Journal  of  Agricultural  Research.  Vol. 

42 


Western  Army  Cutworm 

when  they  are  laid.  The  young  worms  feed  during  the  fall  until  winter 
comes  on.  As  a  rule  little  or  no  damage  is  noticed  as  a  result  of  this  fall 
feeding.  With  the  coming  of  cold  weather  the  worms  become  dormant, 
in  which  condition  they  remain  until  the  coming  of  warm  weather  in  the 
spring,  when  they  resume  feeding. 

In  seasons  of  normal  temperatures  the  worms  feed  until  about  April 
15th  or  May  1st.  If  the  season  is  cold  and  backward  the  feeding  period 
is  prolonged.  Under  such  conditions  the  worms  have  been  known  to 
feed  until  well  into  May. 

Advantage  can  be  taken  of  our  knowledge  of  the  feeding 
habits  of  this  worm  in  the  sowing  of  our  crops.  In  case  we  have 
an  infested  field  it  can  safely  be  planted  to  an  early  maturing  crop  by 
waiting  until  the  worms  have  ceased  feeding,  which  is  normally  about 
the  middle  of  April  in  the  latitude  of  Denver.  Farther  north,  planting 
should  be  delayed  until  about  May  1st  to  10th. 

The  moths  begin  to  appear  in  numbers  about  June  15th.  From 
this  time  until  the  fore  part  of  July  they  are  most  abundant.  They 
often  become  a  nuisance  in  dwellings,  causing  much  annoyance  by 
flying  about  the  lamps.  When  very  numerous  the  moths  will  be  found 
under  any  object  which  affords  concealment  during  the  day.  Old  gar- 
ments hanging  on  the  sides  of  out-buildings  seem  to  be  favorite  hiding 
places.  The  moths  live  until  fall,  when  egg  laying  begins. 

NATURAL  ENEMIES 

There  are  a  number  of  parasitic  and  predacious  insects  which  prey 
upon  the  western  army  cutworm.  The  most  important  of  these  are: 
Ichneumon-flies,  Braconids,  Chalcis-flies  and  ground  beetles  and  certain 
species  of  digger-wasps.  Several  species  of  birds  destroy  great  numbers 
of  cutworms  also. 

Ichneumon-flies,  Braconids  and  Chalcis-flies  sting  their  eggs  into 
the  cutworms,  using  for  this  purpose  a  long  slender  organ  called  an 
ovipositor.  This  ovipositor  is  located  at  or  near  the  tip  of  the  abdomen. 
After  the  eggs  have  been  placed  in  the  body  of  the  cutworm  the  little 
grubs  hatch  and  immediately  begin  feeding.  These  grubs  subsist 
upon  the  body  fluids  and  fatty  substances  of  the  cutworm  but  do  not 
destroy  its  vital  organs  until  they  are  fully  grown. 

Ichneumon-fly 

The  larva  of  the  Ichneumon-fly  10  (Fig.  5,  Plate  I,  Page  11)  does 
not  kill  the  worm,  which  changes  into  a  pupa  before  the  parasite's  work 
is  finished.  The  moth  never  develops  in  a  parasitized  pupa,  however, 
for  the  pupa  is  killed  by  the  parasite,  which  gnaws  its  way  out  when  it 
is  fully  developed.  Instead  of  a  moth  coming  forth  to  lay  more  eggs  to 
infest  our  fields,  the  wasp-like  Ichneumon-fly  emerges,  and  if  a  female 
it  deposits  its  eggs  in  other  cutworms,  thus  carrying  on  the  good  work 
of  ridding  our  fields  of  these  pests. 

Braconid 

The  larvae  of  the  Braconid  2  (Fig.  6,  Plate  I,  Page  1 1)  kill  the  worm 
before  it  changes  to  a  pupa.  When  fully  grown  the  grubs  gnaw  their 
way  out  of  the  worm  and  proceed  to  spin  about  themselves  little  silken 

(lu-2)  See  explanation  of  "Reference  Figures."  page  2. 

43 


Western  Army  Cutworm 

cocoons  (Fig.  7,  Plate  I,  Page  11)  in  which  their  development  is  com- 
pleted. These  cocoons  are  sometimes  fastened  to  the  dead  worm, 
sometimes  to  grasses  or  other  plants,  where  they  cling  in  clusters. 

Chalcis-fly 

The  little  Chalcis-fly  4  (Fig.  8,  Plate  I,  Page  11)  is  one  of  the  most 
interesting  parasites  which  attack  the  cutworms.  The  parasitized 
worms  die  before  changing  into  pupae.  A  single  worm  killed  by  this 
parasite  has  been  known  to  contain  over  2,000  of  these  little  flies.  The 
parasites  complete  their  development  in  the  dead  worm.  Figure  4, 
Plate  IX,  Page  27  shows  a  parasitized  worm  just  before  the  emergence 
of  the  parasites,  the  pupa  of  which  completely  fill  the  skin  of  the  cut- 
worm and  can  be  seen  through  it  as  little  oval  bodies. 

Digger-wasp 

The  digger-wasp  6  (Fig.  18,  Plate  VI,  Page  21)  is  another  very  in- 
teresting natural  enemy  of  cutworms.  The  figure  represents  one  of  these 
insects  carrying  an  army  cutworm  to  its  burrow.  So  interesting  are 
their  habits  that  the  writer  is  giving  the  story  of  the  capture  and  sub- 
sequent entombing  of  a  cutworm  by  a  digger-wasp. 

On  warm  days  in  early  summer  these  blue-black  wasps  can  be  seen 
hurrying  over  the  ground,  in  and  out  of  every  hole,  under  every  clod 
and  into  every  possible  place  where  a  cutworm  could  hide.  In  its  search 
many  short  flights  are  made  and  when  running  the  wings  are  jerked 
nervously,  while  every  movement  of  the  hunter  is  indicative  of  the 
greatest  haste. 

When  a  cutworm  is  found  it  is  immediately  .paralyzed,  apparently 
by  being  stung.  This  does  not  kill  it  but  renders  it  helpless,  in  which 
condition  it  remains  until  destroyed  by  the  larva  of  the  wasp. 

The  next  act  in  this  tragedy  of  nature  is  the  finding  of  a  suitable 
place  to  leave  the  worm  while  a  site  for  the  home  of  the  young  wasp  is 
found.  Always,  so  far  as  observed,  the  worm  is  left  on  some  high  place, 
such  as  the  top  of  a  large  clod  of  earth  or  in  a  fork  of  some  plant  an  inch 
or  two  above  the  ground. 

Dame  wasp  (for  it  is  always  the  female  that  catches  the  cutworms) 
does  not  believe  in  the  old  adage,  "Never  catch  a  bird  until  you  have  a 
cage  for  it,"  as  the  worm  is  always  secured  before  the  burrow  is  dug. 
The  worm  having  been  left  in  some  place  of  prominence,  the  search  for 
a  suitable  location  to  dig  a  burrow  begins.  Mrs.  Fossores  (for  this 
is  one  of  her  names)  does  not  consider  "any  old  place"  good  enough 
for  a  home  for  her  young.  One  wasp  was  seen  to  start  seven  burrows 
before  finding  a  place  entirely  to  her  liking.  The  eighth  location  proved 
satisfactory  and  the  burrow  was  completed.  Several  of  the  unsatis- 
factory attempts  were  made  where  the  soil  was  soft  and  the  digging  easy; 
however,  an  easy  job  did  not  seem  to  be  what  the  wasp  was  looking  for. 
The  location  finally  selected  was  in  a  hard  beaten  pathway  where  the 
digging  was  very  difficult.  Thirty  minutes  were  consumed  in  the  con- 
struction of  the  burrow.  The  wasp  rested  but  once  during  this  period 
and  then  for  but  a  very  short  time,  when  she  lay  flattened  out  on  the 
warm  soil  in  the  sunshine. 

(4-a)  See  explanation  of  "Reference  Figures,"  page  2. 

44 


Western  Army  Cutworm  Pale  Western  Cutworm 

When  the  nest  was  completed  the  wasp  wandered  about  for  several 
minutes  and  finally  went  to  the  worm,  grasped  it  by  the  throat  and 
carried  it  in  almost  a  straight  line  to  the  mouth  of  the  burrow,  where 
it  was  laid  with  its  head  toward  the  opening.  She  then  entered  the 
burrow,  turned  around,  came  out,  and  grasping  the  worm,  backed  into 
the  burrow  again,  dragging  it  after  her.  After  a  few  seconds,  during 
which  time  the  egg  was  fastened  to  the  worm,  the  wasp  reappeared, 
turned  its  head  away  from  the  mouth  of  the  burrow,  and,  standing  on 
her  four  hind  legs,  clawed  dirt  into  it  with  her  front  feet.  Every  little 
while  she  turned  around  to  ram  the  dirt  into  the  opening  with  her  head. 
This  was  continued  until  the  mouth  of  the  burrow  was  completely  filled. 
The  surface  of  the  soil  was  left  in  such  a  condition  that  it  was  only  with 
the  greatest  difficulty  that  the  writer  could  locate  the  burrow. 

The  egg,  shown  fastened  near  the  head  of  the  worm  in  Figure  17, 
Plate  VI,  Page  21,  gradually  changes  into  a  maggot.  The  forward  end 
of  this  maggot,  which  contains  the  mouth,  is  long  and  pointed  and  during 
the  entire  feeding  period  remains  embedded  in  the  body  of  the  worm. 
As  the  larva  increases  in  size  the  worm  shrinks  until,  when  the  grub  is 
fully  grown,  nothing  but  its  empty  skin  remains,  as  shown  in  Figure  16, 
Plate  VI,  Page  21.  When  the  young  wasp  has  exhausted  its  supply  of 
food  its  head  is  withdrawn  from  the  empty  skin  of  the  worm. 

The  next  day  or  so  is  spent  in  lining  its  burrow  with  a  silken  cocoon, 
within  which  the  grub  changes  to  the  pupa  and  finally  into  the  adult 
wasp. 

Birds 

Birds  are  among  the  most  effective  natural  checks  of  cutworms. 
The  meadow  lark  is  probably  one  of  the  most  valuable,  its  food  in  May 
being  about  24%  caterpillars,  the  greater  part  of  which  are  cutworms. 
Blackbirds  of  all  species,  and  robins,  destroy  large  numbers  of  cutworms, 
as  do  many  other  ground  feeding  species. 

(b)     PALE  WESTERN  CUTWORM 

(Figs.  9,  10,  11  and  12,  Plate  I,  Page  11) 

The  pale  western  cutworm  a  2  is  a  western  species  which  until 
1911  was  not  known  as  seriously  injurious.  Reported  outbreaks  have 
all  occurred  in  the  Great  Plains  and  Rocky  Mountain  areas  of  the  United 
States  and  the  prairies  of  Western  Canada. 

Unlike  the  western  army  cutworm,  this  species  does  not  occur  in 
alfalfa  to  any  extent.  Fall  grain,  crops  planted  on  weedy  fallow  land 
and  those  following  grain  are  most  apt  to  be  injured.  Seldom  are  crops 
following  cultivated  crops  injured  unless  they  are  adjacent  to  infested 
fields.  This  is  especially  true  of  crops  following  sugar  beets  and  potatoes. 

DESCRIPTION 
The  Worm 

The  full  grown  worm  (shown  natural  size,  Fig.  9,  Plate  I,  Page  11) 
is  a  dirty,  pale  gray  color.  After  eating  its  fill  of  green  food  it  takes  on 
an  olive  tinge.  The  head  and  part  of  the  first  segment  of  the  body  back 
of  it  are  light  brown.  There  are  usually  two  dark  lines  on  the  head  as 


See  explanation  of  "Reference  Figures."  page  2. 

45 


Pale  Western  Cutworm 

shown  in  the  figure.    The  small  dark  spots  on  the  segments  of  the  abdo- 
men, each  bearing  a  short  stiff  bristle,  are  usually  plainly  visible 

Just  beneath  the  skin  of  the  back  is  an  organ  which  fulfills  the 
offices  of  the  heart  in  the  higher  animals.  This  shows  as  a  dark  line 
in  the  center  of  the  back  running  nearly  the  whole  length  of  the  worm. 
If  watched  closely  it  will  be  seen  to  pulsate  in  true  heart  fashion  when 
the  worm  is  alive. 
The  Pupa 

The  pupa  resembles  that  of  the  western  army  cutworm  so  closely 
that  Figure  2,  Plate  I,  Page  11,  will  suffice  for  both.  Aside  from  some 
minor  structural  differences  the  only  difference  is  in  the  size.  The  pupa 
of  the  species  under  consideration  is  slightly  smaller  than  that  of  the 
western  army  cutworm. 

The  Moth 

Figure  10,  Plate  I,  Page  1 1  represents  the  moth,  natural  size.  The 
whole  insect  is  lighter  than  the  moth  of  the  western  army  cutworm. 
The  colors  are  chiefly  delicate  shades  of  tan  and  brown.  These  moths 
fly  more  freely  during  the  day  than  those  of  the  preceding  species.  On 
warm  afternoons  in  fall  they  have  been  seen  feeding  on  the  blossoms  of 
"rabbit  brush"  in  quite  large  numbers. 

LIFE  HISTORY 

The  life  history  of  the  pale  western  cutworm  is  essentially  the  same 
as  that  of  the  western  army  cutworm.  The  only  important  differences 
are  in  the  dates  when  feeding  ceases  and  the  changes  from  worm  to  pupa 
and  pupa  to  moth  take  place.  For  a  description  of  how  and  where  these 
changes  take  place  read  those  parts  of  the  discussion  of  the  western 
army  cutworm  under  the  heads  "The  Pupa"  and  "The  Moth'  '(Page  41). 

This  cutworm  is  single  brooded  in  Northern  Colorado.  The  eggs, 
shown  very  much  enlarged  in  Figures  1 1  and  12,  Plate  I,  Page  1 1,  are  a 
little  less  than  fa  of  an  inch  in  diameter.  The  eggs  are  laid  during 
September  and  October,  and  so  far  as  known  are  deposited  either  in 
cracks  in  the  soil,  on  lumps  of  soil  or  on  the  surface  of  the  soil.  Seldom, 
if  ever,  are  they  deposited  on  green  plants.  Dry,  fallow  land  and  stubble 
fields  are  ideal  locations  for  egg  laying. 

During  open,  warm  falls  some  eggs  may  hatch  before  winter  sets  in, 
but  field  observations  indicate  that  the  greater  part  of  the  eggs  do  not 
hatch  until  spring.  As  soon  as  hatched  the  worms  begin  feeding  and 
continue  to  feed  until  the  last  of  June  or  the  first  or  second  week  of  July. 
Because  of  this  late  feeding  habit  late  planting  cannot  be  re- 
sorted to  as  a  means  of  preventing  loss,  as  no  profitable  field 
crop  can  be  planted  at  this  late  date. 

The  worms  remain  in  their  earthen  cells  for  two  or  three  weeks 
before  the  change  to  the  pupa  takes  place.  In  about  four  weeks  more 
the  moth  emerges. 

NATURAL  ENEMIES 

Little  is  known  of  the  natural  enemies  of  the  pale  western  cutworm. 
In  all  probability  it  is  held  in  check  by  some  of  the  same  parasitic  and 
predacious  insects  and  birds  as  the  western  army  cutworm. 

46 


Variegated  Cutworm 

(c)     VARIEGATED  CUTWORM 

(Figs.  7  and  15,  Plate  VII,  Page  23) 

This  is  one  of  the  most  universally  distributed  of  all  cutworms.  It 
is  known  over  practically  the  whole  agricultural  world  with  the  possible 
exception  of  Africa.  At  one  time  or  another  damaging  outbreaks  of 
this  worm  have  occurred  in  nearly  every  part  of  its  range.  While,  so 
far  as  the  author  knows,  no  serious  outbreak  has  occurred  in  the  sugar 
beet  growing  sections  of  the  West  which  come  within  the  scope  of  this 
Bulletin,  yet  it  is  always  present  in  our  fields  and  may  at  any  time  appear 
in  such  numbers  as  to  do  considerable  damage. 

This  worm  is  a  very  general  feeder,  attacking  almost  any  green 
plant.  It  seems  to  prefer  cultivated  plants,  and  feeds  sparingly  upon 
weeds,  grasses  and  grains. 

NATURE  OF  INJURY 

The  feeding  habits  of  the  variegated  cutworm  differ  in  some  respects 
from  those  of  the  preceding  species.  In  California  it  is  reported  as 
damaging  young  sugar  beets  in  April.*  At  this  time  the  worms  spent 
the  day  buried  in  the  soil,  coming  out  to  feed  during  the  night  and  early 
morning.  The  beets  were  eaten  off  near  the  surf  ace  of  the  ground  in  true 
cutworm  fashion.  During  the  same  season  a  later  brood  of  worms  fed 
upon  the  leaves,  entirely  stripping  the  plants  of  foliage.  The  roots  were 
also  damaged  to  some  extent.  Large  numbers  of  these  worms  have  been 
observed  in  Northern  Colorado  on  the  third  cutting  of  alfalfa. 

METHODS  OF  CONTROL 

While  the  author  has  had  no  experience  in  the  control  of  this  cut- 
worm, it  would  seem  that  during  the  early  part  of  the  season,  before 
the  worms  have  acquired  the  climbing  habit,  the  poisoned  bait  so  suc- 
cessfully used  against  the  western  army  and  pale  western  cutworms 
would  be  equally  successful  in  the  control  of  this  species. 

In  the  case  of  later  broods  or  when  the  worms  are  feeding  upon  the 
leaves,  spraying  with  Paris  green  will  give  satisfactory  results,  according 
to  Mr.  G.  E.  Bensel.*  In  his  work  in  California  Mr.  Bensel  used  2  pounds 
of  Paris  green  to  50  gallons  of  water.  To  this  about  1  Ib.  of  molasses 
was  added  to  make  the  poison  adhere  to  the  leaves.  Two  or  three 
applications  were  required,  at  a  cost  of  about  90  cts.  per  acre,  to  check  the 
worms.  A  traction  sprayer  should  be  used  in  order  to  secure  an  even 
application  and  an  economic  use  of  the  poison. 

Large  lantern  traps  were  also  used  to  catch  the  moths  in  Ventura 
Co.,  California,  with  very  satisfactory  results. 

DESCRIPTION 
The  Egg 

The  eggs  resemble  those  of  other  cutworms.  They  are  deposited 
in  clusters  of  from  a  few  to  as  high  as  50  or  60  on  the  twigs  of  trees  and 
leaves  of  various  plants. 

*G  E  Bensel.  "Control  of  the  Variegated  Cutworm  in  Ventura  County.  California."  Journal  of 
Economic  Entomology.  Vol.  9.  No.  2  (April.  1916). 

47 


Variegated  Cutworm  White  Grubs 

The  Worm 

The  worm  (Fig.  7,  Plate  VII,  Page  23)  is  variable  in  color,  ranging 
from  a  very  pale  to  almost  a  dark  brown.  Some  light  individuals  have 
a  greenish  tinge.  The  upper  part  is  mottled  with  various  shades  of 
brown  and  in  the  darker  worms  some  black.  On  each  side  is  a  con- 
spicuous yellow  stripe  and  above  this  a  dark  stripe  broken  into  a  row 
of  crescent  spots,  as  shown  in  the  figure.  The  most  characteristic  mark- 
ing is  the  row  of  yellow  spots  in  the  center  of  the  back  on  the  forward 
half  of  the  body. 

The  Moth 

The  moth,  like  the  worm,  varies  in  color.  The  one  shown  in  Figure 
15,  Plate  VII,  Page  23,  is  of  the  dark  type,  the  other  extreme  being  very 
much  lighter,  while  all  gradations  of  color  between  the  two  occur.  Like 
the  moths  of  most  cutworms,  the  adult  variegated  cutworm  flies  princi- 
pally during  the  night  when  it  is  attracted  by  strong  lights.  Advantage 
of  this  fact  is  sometimes  taken  in  applying  control  measures. 

LIFE  HISTORY 

As  is  likely  to  be  the  case  with  insects  which  range  over  so  large 
a  territory,  the  seasonal  history  of  the  variegated  cutworm  varies  with 
the  locality.  It  is  known  to  pass  the  winter  in  every  stage  from  the  egg 
to  the  adult  moth,  depending  upon  the  latitude.  In  Northern  Colorado 
it  probably  passes  the  winter  in  the  pupal  stage  or  as  a  partly  grown 
worm.  There  are  two,  possibly  three,  generations  produced  annually 
in  the  latitude  of  Northern  Colorado.  The  damage  is  done  largely  by 
the  first  and  second  broods.  The  third  brood,  when  produced,  usually 
comes  too  late  to  do  any  great  damage  during  the  fall.  However,  these 
late  hatched  worms  may  hibernate  over  winter,  in  which  case  damage 
may  be  done  the  following  spring. 

2.    WHITE  GRUBS 

(Figs.  19,  20  and  23,  Plate  I,  Page  11) 

White  grubs  are  the  larvae  of  several  species  of  rather  robust  beetles 
commonly  known  as  May  beetles  or  June  bugs.  These  beetles  often 
enter  houses  at  night,  being  attracted  by  the  lights.  At  such  times 
they  fly  awkwardly  about,  their  wings  making  a  loud  humming  noise. 
Their  flight  usually  ends  abruptly  as  they  collide  with  the  wall  or  some 
object  in  the  room  and  fall  heavily  to  the  floor. 

These  insects  belong  to  a  large  family,  some  species  of  which  are 
scavengers,  while  others  feed  upon  living  plants.  The  latter  do  much 
damage  to  crops,  especially  in  the  Mississippi  Valley  and  eastward. 

The  Sacred  Beetle  of  Egypt  belongs  to  this  family.  This  beetle 
was  held  in  high  veneration  by  the  ancient  Egyptians.  It  was  placed  in 
the  tombs  with  their  dead.  The  members  of  this  group  we  know  as 
"tumble-bugs,"  from  their  habit  of  rolling  about  large  balls  of  dung  in 
which  their  eggs  are  laid.  To  the  Egyptians  this  ball  was  symbolic  of 
the  earth  and  the  beetle  of  the  sun.  The  thirty  joints  of  the  feet  were 
taken  to  represent  the  days  of  the  month.  It  was  supposed  that  all  of 
these  beetles  were  males.  This  was  taken  to  symbolize  a  race  of  warriors, 

48 


White  Grubs 

a  superstition  which  reached  as  far  as  Rome,  where  the  soldiers  wore 
images  of  the  beetles  as  sets  in  their  rings. 

The  grubs  of  some  species  lie  on  their  backs  in  the  soil.  This  is 
responsible  for  a  myth  of  the  Cherokee  Indians*  which  runs  something 
like  this: 

In  the  old  days  the  beasts,  birds,  fishes,  insects  and  plants  could 
all  talk  and  they  and  the  people  lived  together  in  peace  and  friendship. 
As  time  went  on  the  people  became  so  numerous  that  they  began  to  crowd 
the  poor  animals  until  they  became  cramped  for  room.  Worse  yet, 
man  invented  bows,  knives,  blow-guns,  spears  and  hooks  and  began  to 
kill  the  birds,  animals  and  fishes  for  food  and  to  tread  upon  the  smaller 
creatures,  such  as  frogs  and  worms,  out  of  pure  contempt.  So  the  animals 
decided  to  hold  a  council  to  determine  upon  measures  for  their  common 
safety. 

The  bears  met  first.  After  each  had  complained  about  how  man 
killed  their  friends,  ate  their  flesh  and  used  their  skins  for  robes,  it  was 
decided  to  begin  war  against  man  at  once.  Some  one  asked  what  weapons 
man  used.  "Bows  and  arrows,"  was  the  answer.  The  bears  decided 
to  try  fighting  man  with  his  own  weapons.  One  bear  got  a  fine  piece  of 
locust  wood  for  the  bow.  Another  sacrificed  himself  for  the  good  of  his 
friends  that  his  entrails  might  be  used  for  bow  strings.  But,  alas,  it  was 
found  that  the  bears'  long  claws  spoiled  the  shot.  Some  one  proposed 
that  their  claws  be  trimmed.  This  was  done  and  the  arrow  flew  straight 
to  the  mark.  The  leader,  a  large  white  bear,  objected,  saying  that  all 
bears  needed  claws  in  order  to  climb  trees.  "It  is  better  to  depend 
upon  teeth  and  claws  that  nature  gave  us,  for  it  is  evident  that  man's 
weapons  are  not  for  us." 

The  deer  held  council  next  and  decided  to  send  rheumatism  upon  the 
hunter  who  killed  one  of  them  unless  he  took  care  to  ask  their  pardon 
for  the  offense. 

Next  the  fishes  and  reptiles  held  council  and  decided  to  cause  man  to 
dream  of  snakes  twisting  about  him  in  slimy  folds  or  of  eating  decayed 
fish  so  that  he  would  sicken  and  die. 

Finally  the  birds,  insects  and  other  small  animals  came  together  in 
council.  The  grubworm  was  chief  of  the  assembly.  After  all  had  made 
complaint  about  the  cruelties  of  man  they  began  to  name  the  different 
diseases  with  which  he  should  be  afflicted.  As  disease  after  disease  was 
named,  the  grubworm  became  so  happy  that  he  finally  shook  for  joy  and 
fell  over  backward  and  was  unable  to  rise  but  had  to  wriggle  off  on  his 
back,  as  the  grubworm  has  done  ever  since. 

When  the  plants  heard  what  had  been  done  by  the  animals  they 
decided  to  defeat  their  evil  designs.  So  each  tree,  shrub  and  herb,  down 
even  to  the  grasses  and  mosses,  agreed  to  furnish  a  cure  for  some  one  of 
the  diseases.  Thus  came  medicine. 

NATURE  OF  INJURY 

White  grubs  never  appear  above  ground  but  live  and  feed  below  the 
surface.  They  are  naturally  grass-land  inhabitants,  being  most  common 
in  pasture  and  meadow  land,  where  they  feed  on  the  roots  of  the  grasses. 

•"Myths  of  the  Cherokee."  Nineteenth  Annual  Report  of  the  U.  S.  Bureau  of  Ethnology  (1898). 

49 


White  Grubs 

Sugar  beets,  potatoes  and  corn  are  among  the  field  crops  most  seriously 
damaged.  Garden  truck  and  strawberries  often  suffer  heavily,  also. 

In  the  case  of  potatoes  and  sugar  beets  deep  pits  are  eaten  into  the 
tubers  and  roots.  If  sugar  beets  are  damaged  when  the  plants  are  small 
the  root  is  eaten  off  two  or  three  inches  below  the  surface  of  the  ground. 
The  plant,  of  course,  wilts.  If  it  is  pulled  the  tip  of  the  root  at  the  point 
where  it  is  eaten  off  will  be  dark  in  color,  sometimes  almost  black.  Wire- 
worm  injury  is  so  similar  to  this  that  the  two  are  easily  confused.  Later 
in  the  season  when  the  beets  have  attained  some  size  they  may  not  be 
entirely  eaten  off  but  portions  of  their  surface  will  be  eaten  away.  Beets 
attacked  at  this  time  of  the  year  usually  wilt,  especially  in  the  heat  of 
the  day.  Such  beets  are  easily  pulled  because  the  grubs  have  destroyed 
most  of  the  smaller  roots.  When  removed  from  the  soil,  the  surface 
will  be  found  pitted,  the  pits  being  dark  in  color  and  rough  on  the  surface. 

The  adults  (beetles)  of  many  of  the  injurious  June  bugs  feed  upon 
the  leaves  of  various  trees,  mainly  cottonwoods  and  willows  in  the  beet- 
growing  areas  covered  by  this  Bulletin.  Injury  by  white  grubs  has  been 
noted  only  in  river  bottoms  where  natural  sod  and  the  trees  mentioned 
above  are  both  common.  Crops  following  sod  or  crops  in  which 
much  grass  was  allowed  to  grow  are  most  apt  to  be  injured. 

METHOD  OF  CONTROL 

There  is  no  known  method  by  which  an  infested  field  can  be  freed 
of  white  grubs  without  injury  to  growing  crops.  However,  measures  can 
be  taken  which  will  reduce  the  injury  or  prevent  future  losses. 

Pasturing  with  Hogs 

When  practical,  pasturing  with  hogs  will  rid  land  of  grubs.  There 
is  one  drawback  to  this  method,  however.  This  lies  in  the  fact  that  the 
giant  thorn-headed  worm,  an  internal  parasite  of  swine,  passes  one  stage 
of  its  life  in  certain  white  grubs.  Hogs  eating  these  grubs  become  in- 
fested and  grubs  eating  the  excrement  of  such  animals  become  infested 
in  turn.  If  no  hogs  have  been  pastured  on  land  for  at  least  three  years, 
grubs  in  it  will  not  contain  this  parasite,  and  hogs  pastured  on  such  land 
will  not  become  infested. 

Rotation 

White  grub  losses  can  be  reduced  by  practicing  a  proper  system  of 
rotation.  Since  the  beetles  usually  deposit  their  eggs  in  fields  of  grass  or 
small  grain,  sugar  beets,  potatoes  or  corn  should  not  follow  these  crops  in 
localities  where  grubs  occur  unless  the  ground  is  known  to  be  free  from 
them.  Alfalfa,  clover,  buckwheat,  peas  and  small  grain  are  not  damaged 
to  the  same  degree  as  the  crops  mentioned  above. 

Plowing 

Fall  plowing,  if  done  early,  is  a  great  help  in  destroying  this  pest. 
As  the  grubs  burrow  deep  into  the  soil  as  cold  weather  comes  on,  to  be 
effective,  fall  plowing  must  be  done  not  later  than  October.  Fall  plow- 
ing is  much  more  effective  if  followed  by  the  disc  or  harrow.  Plowing 
infested  land  in  July  or  August  will  destroy  many  beetles,  as  the  change 
from  pupa  to  adult  takes  place  about  this  time  and  the  newly  trans- 
formed beetles  are  easily  killed. 

50 


White  Grubs 

LIFE  HISTORY 

The  life  histories  of  the  May  beetles  are  not  very  well  known.  Few 
records  exist  of  the  raising  of  beetles  from  the  egg.  In  all  probability 
most,  if  not  all,  of  the  injurious  species  occurring  in  the  beet  growing 
sections  of  the  arid  West  have  a  three  year  life  cycle.  It  is  possible  that 
the  same  species  may  complete  its  development  in  two  years  in  the  South, 
in  three  years  in  the  northern  tier  of  states,  and  require  four  in  Canada. 

In  general,  the  life  cycle  of  the  white  grub  is  as  follows :  The  beetles 
lay  their  eggs  in  the  soil  in  early  summer.  As  soon  as  the  young  grubs 
hatch  they  begin  to  feed.  At  this  time  they  seem  to  prefer  decaying 
vegetable  matter,  although  when  very  numerous  they  are  known  to 
attack  and  damage  growing  crops.  Feeding  continues  until  the  approach 
of  cold  weather,  when  the  grub  burrows  deep  into  the  soil,  where  it  spends 
the  winter  in  hibernation.  Usually  the  damage  done  during  the  first 
season  of  the  grub's  life  is  slight. 

With  the  return  of  spring  the  grubs  come  toward  the  surface,  where 
they  begin  a  season-long  campaign  against  the  farmers'  crops.  It  is 
during  this  second  year  of  their  lives  that  the  grubs  do  the  most  damage. 
At  this  age  the  grub  appears  as  in  Figure  19,  Plate  I,  Page  11. 

Again  with  the  coming  of  winter  the  grub  burrows  into  the  soil, 
returning  to  the  surface  the  following  spring  to  feed  a  few  weeks.  The 
change  from  grub  to  pupa  takes  place  about  the  first  of  June.  After 
remaining  in  this  resting  stage  for  several  weeks  the  adult  beetle  emerges 
from  the  pupa.  The  beetles  do  not  leave  the  soil  until  the  following 
spring,  however.  Digging  their  way  out  of  the  soil  during  May,  the 
beetles  proceed  to  feed,  mate  and  deposit  the  eggs  for  another  generation 
of  grubs. 

Figure 23,  Plate  I,  Page  11  represents  the  adult  of  a  common  white 
grub  which  sometimes  occurs  in  fields  in  our  river  bottoms. 

Figure  20,  Plate  I,  Page  11  is  the  grub  of  a  small  species  which  is 
found  in  newly  broken  alfalfa  ground  and  is  often  mistaken  for  the  young 
grubs  of  injurious  species.  So  far  as  known  it  feeds  only  upon  rotting 
vegetable  matter  and  not  upon  crops. 

NATURAL  ENEMIES 

The  white  grub  is  preyed  upon  by  many  birds,  animals  and  insects, 
which  materially  aid  in  holding  it  in  check.  The  U.  S.  Biological  Survey 
has  found  this  insect  in  the  stomachs  of  60  species  of  common  birds.  Of 
the  feathered  enemies  of  the  white  grub  the  crow  and  the  crow  blackbird 
are  no  doubt  the  most  important.  Both  of  these  birds  will  follow  the 
plow  in  grub  infested  fields  and  search  out  the  grubs  exposed.  The 
number  of  grubs  which  a  crow  blackbird  will  eat  at  one  time  is  almost 
beyond  belief.  It  has  been  reported*  that  one  bird  ate  20  grubs  in  about 
two  minutes. 

Skunks  are  very  fond  of  white  grubs.  Meadow  lands  are  often  so 
thoroughly  worked  over  by  these  animals  that  hardly  a  square  yard  over 
large  areas  does  not  contain  one  or  more  of  the  shallow  holes  from  which 
a  grub  has  been  taken. 

*J.  I.  Davis.  "Common  White  Grubs."  Farmers'  Bulletin  No.  543,  U.  S.  Department  of  Agricul- 
ture (1913). 

51 


White  Grubs 


Wireworms 


Parasitic  and  predacious  insects,  while  they  destroy  many  of  the 
grubs,  and  beetles  as  well,  are  of  less  importance  seemingly  than  the  bird 
and  mammal  enemies  of  this  pest.  In  the  Farmers'  Bulletin  mentioned,* 
Mr.  Davis  names  two  wasps,  "  Tiphia  inornata  Say., "  and  "  Ells  sexcincta 
Fab.,"  and  a  parasitic  fly,  " Pyrgota  undata."  The  first  two  destroy 
the  grubs  and  the  last  preys  upon  the  beetles. 

3.     WIREWORMS 

(Figs.  13,  14,  15,  16,  17,  18,  Plate  I,  Page  11) 

Few  boys  and  girls  grow  to  manhood  and  womanhood  on  the  farm 
without  becoming  familiar  with  the  "snapping-beetles,"  "skip-jacks," 
or  "click-beetles,"  as  adult  wireworms  are  called.  (Figs.  16  and  17,  Plate 
I,  Page  11,  and  Fig.  5,  Page  52.) 

Many  a  dull  moment  has  been  en- 
livened by  the  acrobatic  performances  of 
these  trim,  slender  bodied  beetles  which 
drop  as  if  dead,  when  touched.  With 
their  legs  closely  folded  against  their 
bodies  they  feign  death  until  they  think 
all  danger  is  past,  when  they  are  off  for 
cover  as  fast  as  they  can  travel.  If  they 
happen  to  fall  on  their  backs  they  will 
spring  into  the  air  several  inches,  turn 
over,  land  on  their  feet,  and  are  off  at 
a  run.  This  springing  is  accompanied 
by  a  sharp  snap  or  click,  therefore  the 
names  "snapping-beetles"  and  "click- 
beetles." 

There  are  over  500  species  of  these 
insects  found  in  the  United  States. 
The  larvae  of  many  of  these  live  in  the 
decaying  wood  of  stumps  and  fallen  trees. 
Many  others  are  denizens  of  the  soil. 
Among  the  latter  are  the  injurious  forms. 
These  are  most  apt  to  be  found  in  pasture 
and  meadow  lands  or  wherever  grass  is 
allowed  to  grow  about  the  fields.  A  few 
species  are  known  to  be  predacious,  feed- 


Fig.  5.       Adult  Snapping-beetle,  Alan 

ioculatus.      The  larvae  of  this  beetle 

feed  upon  decaying  wood. 


ing  upon  other  insects  and  often  upon  their  own  kind. 

NATURE  OF  INJURY 

During  the  early  part  of  the  season,  especially  about  the  time  the 
beets  are  being  blocked  and  thinned,  here  and  there  a  beet  will  be  found 
which  is  apparently  dying.  The  leaves  will  be  wilted,  many  times  the 
outer  ones  being  dead  and  dry.  When  such  beets  are  pulled  they  will  be 
be  found  gnawed  off  an  inch  or  two  below  the  surface  of  the  ground. 
The  end  of  the  beet  as  it  comes  from  the  soil  will  usually  be  dark,  almost 

*J.  J.  Davis.  •'Common  White  Grubs."  Farmers'  Bulletin  No.  543.  U.  S.  Department  of  Agriculture 


52 


Wireworms 

black.  This  wilting  of  the  leaves,  associated  with  the  darkening  of  the 
tip  where  it  is  gnawed  off,  are  characteristic  of  wireworm  injury;  how- 
ever, the  work  of  white  grubs  is  very  similar  in  the  early  part  of  the  season. 

Many  times  beets  eaten  off  by  wireworms  will  throw  out  new  roots, 
especially  if  the  soil  is  moist.  Such  beets  develop  a  short  sprangly  root 
as  a  rule.  If  the  soil  is  dry  and  the  weather  warm  the  injured  plants 
usually  die.  This  results  in  a  poor  stand  if  the  injury  is  severe. 

Wireworm  injury  to  sugar  beets  is  not  so  severe  in  the  Great  Plains 
States  as  it  is  farther  east  and  in  California.  In  the  latter  state  the 
damage  is  especially  severe  and  is  due  to  the  sugar  beet  wireworm,  which 
is  very  numerous  in  the  beet  fields  of  some  parts  of  that  state. 

This  wireworm  also  damages  alfalfa,  corn  and  beans. 

METHODS  OF  CONTROL 

Because  of  the  great  similarity  between  the  habits  and  life  history  of 
white  grubs  and  wireworms,  many  of  the  same  methods  of  control  may 
be  used  against  both. 

Rotation 

As  already  stated,  wireworms  are  most  likely  to  be  found  in  abund- 
ance in  pasture  and  meadow  lands.  When  such  lands  are  broken  up 
and  planted  to  field  crops  those  least  apt  to  be  badly  injured  should  be 
put  in  the  first  season.  Row  crops,  such  as  sugar  beets,  corn  or 
potatoes,  suffer  most  severely  on  infested  ground.  While  the 
small  grains  are  sometimes  severely  injured  they  are  not  as  a  rule  so 
badly  damaged  as  corn  and  root  crops. 

Short  rotations  in  which  the  land  is  not  allowed  to  remain  in  grass 
for  any  length  of  time  will  prevent  the  increase  of  wireworms,  as  the 
females  prefer  grass  lands  as  places  to  deposit  their  eggs. 

Plowing 

Early  fall  and  late  summer  plowing  will  kill  many  newly  transformed 
beetles  and  pupae,  especially  if  the  surface  is  thoroughly  worked  with  the 
disc  or  harrow. 

Seed  Treatment 

Sometimes  wireworms  injure  seed  corn  before  it  germinates,  thus 
causing  an  almost  total  loss  of  stand  in  severe  cases.  Treating  the  corn 
before  planting  by  coating  it  with  gas  tar  and  dusting  with  Paris  green 
will  almost  entirely  prevent  loss,  according  to  tests  conducted  by  Dr.  H. 
T.  Fernald  in  Massachusetts  in  1908  and  1909. 

Poisoned  Bait 

Many  poisoned  baits  have  been  tried,  but  with  very  little  success. 

DESCRIPTION 
The  Worm 

Wireworms  vary  in  form  and  color  as  well  as  size.  The  species  most 
injurious  to  sugar  beets  resemble  Figure  13,  Plate  I,  Page  11.  This  is 
the  larva  of  the  "click-beetle"  (Fig.  16,  Plate  I).  Figure  14,  Plate  I,  is 
an  outline  drawing  of  the  last  segment  of  the  body  of  this  worm.  The 
notch  in  the  center  is  characteristic  of  many  of  our  injurious  wireworms. 
Figure  18,  Plate  I  represents  another  species  often  found  in  our  fields. 

53 


Wireworms 

The  Pupa 

The  pupal  stage  (Fig.  15,  Plate  I)  is  spent  in  an  oval  cell  in  the  soil. 
The  figure  represents  the  pupa  on  the  beetle  shown  in  Figure  16,  Plate  I. 

The  Beetle 

The  beetles  of  this  group  are  characterized  by  the  freely  moving  joint 
between  the  thorax  and  abdomen  and  by  their  power  to  spring  into  the 
air  when  placed  on  their  backs. 

Our  most  common  species  5  (Fig.  16,  Plate  I)  is  dark  brown.  Figure 
17,  Plate  I,  represents  a  smaller,  lighter  colored  species.  The  drawing 
to  the  right  of  the  colored  figure  is  the  natural  size  of  this  beetle. 

LIFE  HISTORY 

The  life  history  of  the  soil-inhabiting  species  of  wireworms  is  very 
similar  to  that  of  the  white  grubs.  The  eggs  are  laid  in  the  soil. 
Usually  meadows,  pastures  or  other  grass  covered  lands  are  selected  by 
the  females  as  places  to  deposit  their  eggs. 

Two  or  three  years  are  required  for  the  worms  to  reach  maturity. 
Feeding  takes  place  each  season.  When  mature  the  worm  forms  an  oval 
cell  in  the  soil  in  which  the  change  to  the  pupal  stage  takes  place.  This 
change  occurs  during  the  summer  months.  In  the  course  of  a  few  weeks 
the  adult  beetle  emerges  from  the  pupa. 

Most  of  the  newly  transformed  beetles  remain  in  the  soil  until  the 
following  season.  However,  a  few  leave  their  pupal  cells  soon  after 
emerging.  During  the  following  winter  these  beetles  hibernate  under 
dead  leaves,  crop  refuse  or  other  material  which  furnishes  suitable  pro- 
tection against  the  cold  and  moisture. 

NATURAL  ENEMIES 
Ground  Beetles 

Wireworms  are  unusually  free  from  attack  by  parasitic  insects,  but 
the  predacious  ground  beetles  destroy  many  of  them.  Several  species 
of  the  Genus  Calosoma,  one  of  which  is  represented  in  Figure  2,  Plate 
IX,  Page  27,  and  their  larvae,  feed  freely  on  this  pest. 

Birds 

Many  species  of  birds  are  very  effective  in  destroying  the  beetles. 
The  ill-famed  crow  is  a  noted  wireworm  destroyer.  The  food  of  the 
California  shrike,  or  butcher-bird  as  it  is  sometimes  called,  is  known  to 
consist  largely  of  adult  wireworms  during  certain  seasons  of  the  year  and 
where  these  are  abundant.  From  90%  to  95%  of  the  food  eaten  is 
composed  of  these  beetles  at  such  times,  according  to  observations 
recorded  by  John  E.  Graf,  in  Bulletin  No.  123,  Bureau  of  Entomology, 
U.  S.  Department  of  Agriculture. 
Skunks 

Skunks,  which  are  so  effective  in  the  destruction  of  white  grubs, 
devour  large  numbers  of  wireworms  as  well  as  the  adult  beetles.  In 
1914  the  writer  examined  a  quantity  of  excrement  of  the  little,  spotted 
skunk.  No  evidence  of  any  other  animal  food  aside  from  insects  was 
found.  Over  10%  of  the  insects  eaten  were  wireworms  and  click-beetles. 

(•)  See  explanation  of  "Reference  Figures,"  page  2 

54 


Sugar  Beet  Root-louse 
B.     SUCKING  ROOT  FEEDERS 

I.     SUGAR  BEET  ROOT-LOUSE 

(Figs.  1  to  9,  11  to  13,  16  to  18,  Plate  II,  Page  13) 

Because  of  its  universal  distribution  in  the  sugar  beet  growing  sections 
of  the  West  and  the  difficulty  of  controlling  it,  the  sugar  beet  root-louse 
presents  one  of  the  most  serious  insect  pest  problems  with  which  the 
beet  growers  and  factory  people  have  to  contend. 

NATURE  OF  INJURY 

Visible  effects  of  root-louse  injury  on  the  above-ground  parts  of  the 
sugar  beet  do  not  appear  until  the  number  of  lice  becomes  very  great. 
At  such  times  the  color  of  the  beet  leaves  changes  from  a  dark  to  a  yel- 
lowish green.  This  change  in  color  alone  must  not,  however,  be  taken 
as  proof  that  a  crop  is  being  greatly  damaged  by  root-lice.  Sugar  beets, 
especially  when  grown  on  light  soil  or  watered  too  heavily,  will  turn 
light  in  color  in  the  latter  part  of  the  season  when  not  infested  with  root- 
lice.  When  the  lice  become  very  numerous  the  beet  leaves  wilt  as  though 
the  crop  were  suffering  from  lack  of  water.  Often  the  beets  become  so 
shrunken  as  to  be  loose  in  the.  ground  and  very  much  wrinkled.  Such 
beets  are  very  limber  and  can  be  bent  almost  double  without  breaking. 

The  above  is  descriptive  of  exceptional  cases.  Whether  effects  are 
visible  or  not,  if  lice  are  present,  on  the  surface  of  the  roots  and  in  the 
soil  surrounding  them  will  be  found  a  whitish,  mold-like  substance. 
Intermingled  with  this  and  covered  by  it  will  be  seen  many  small,  wingless 
lice  of  a  yellowish  white  color  (Fig.  Q,  Plate  II,  Page  13),  and  if  the  season 
is  well  advanced  some  darker  winged  lice  (Fig.  7,  Plate  II,  Page  13)  as 
well. 

The  effect  of  lice  on  live  stock  is  so  well  known  that  no  one  expects 
a  lousy  animal  to  make  normal  growth  or  put  on  fat.  The  loss  of  blood 
and  possibly  the  irritation  caused  by  the  feeding  of  the  lice  stunt  it  and 
produce  a  very  scrubby  and  inferior  animal.  The  effect  of  lice  on  a  sugar 
beet  may  be  compared  with  that  of  lice  on  livestock.  The  lice  take  up 
the  sap  of  the  beet  and  the  feeding  irritates  it.  The  combined  effect  of 
these  two  things  is  a  small,  stunted  beet  and  one  low  in  sugar  content. 
Of  course  quite  satisfactory  yields  and  sugar  contents  are  possible  even 
though  the  beets  are  lousy.  Nevertheless,  nothing  is  more  certain  than 
that  had  they  not  been  lousy  both  would  have  been  higher. 

Carefully  conducted  tests  show  that  infested  beets  contain  from  £% 
to  1  %  less  sugar  than  uninfested  beets  in  the  same  field.  Also,  the  purity 
of  juice  of  such  beets  is  from  1%  to  2%  lower  than  uninfested  beets. 
The  average  infestation  reduces  the  yield  by  more  than  1  ton  per  acre. 
In  very  severe  cases  the  beets  are  killed  or  made  worthless  for  factory 
purposes. 

METHODS  OF  CONTROL 

There  is  no  known  means  of  entirely  preventing  sugar  beet  root- 
louse  losses.  However,  if  the  crop  is  properly  handled  they  can  be 
greatly  reduced. 

55 


Sugar  Beet  Root-louse 

Irrigation 

It  has  been  shown  by  Mr.  J.  R.  Parker  of  the  Montana  Experiment 
station*,  that  the  sugar  beet  root-louse  does  not  multiply  so  rapidly  in 
moist  as  in  dry  soil.  Experiments  conducted  by  him  on  The  Great 
Western  Sugar  Company's  farm  at  Edgar,  Montana,  and  on  the  Gov- 
ernment Reclamation  Project  at  Huntley,  Montana,  show  that  fields 
irrigated  during  the  migration  of  the  lice  from  the  cotton -wood 
trees  to  the  beet  fields  are  much  freer  from  root-lice  at  harvest 
than  fields  not  irrigated  until  later. 

Migration  begins  about  the  10th  of  June  and  is  at  its  height  about 
the  20th  of  the  month  in  the  latitude  of  Denver,  Colorado.  In  the  lati- 
tude of  Billings,  Montana,  the  height  of  migration  is  probably  reached 
six  to  eight  days  later.  Since  the  losses  due  to  this  insect  are  propor- 
tional to  the  number  of  lice  present  and  feeding  on  the  crop,  anything 
which  reduces  their  number  reduces  the  loss  as  well.  Frequent  irriga- 
tions during  the  growing  season  reduce  the  infestation  and  also  increase 
the  yield  of  beets. 

In  a  leaflet  issued  by  Mr.  Parker  and  circulated  by  The  Great  West- 
ern Sugar  Company  at  Billings,  Montana,  the  results  of  several  years' 
work  in  the  control  of  the  sugar  beet  root-louse,  show  that  there  are  56.2, 
46.6  and  25.6  beets  out  of  every  100  infested  where  two,  three  and  five 
irrigations  respectively  were  applied. 

The  sugar  content  was  15.8%,  17.1%  and  17.2%  for  two,  three  and 
five  irrigations  respectively. 

The  gross  returns  per  acre  were  $82.27  for  two,  $85.61  for  three,  and 
$96.07  for  five  irrigations. 

To  some,  early  irrigation  may  seem  like  "jumping  from  the  frying 
pan  into  the  fire, "  since  it  is  quite  generally  believed  that  early  watering 
is  detrimental  to  sugar  beets.  Quite  to  the  contrary  it  has  been  found 
that  irrigating  as  early  as  June  22nd  produces  better  results  in  yield  and 
per  cent  of  sugar  in  the  majority  of  years.  It  is  a  fortunate  coincidence 
that  early  irrigation  gives  best  results  in  just  the  years  which  are  favor- 
able for  the  development  of  root-lice;  i.  e.,  years  when  the  winter  and 
early  summer  are  dry. 

Through  experiments  conducted  on  The  Great  Western  Sugar  Com- 
pany's Experimental  Farm  at  Longmont,  Colorado,  it  has  been  found 
that,  as  an  average  of  six  years  tests,  irrigating  as  early  as  June  22nd  to 
25th  has  produced  a  yield  of  14.66  tons  per  acre  and  16.05%  sugar,  while 
beets  irrigated  the  first  time  July  5th  to  10th  gave  a  yield  of  but  14.23 
tons  per  acre  and  a  sugar  content  of  15.84%.  Both  the  early  and  late 
irrigated  beets  were  watered  three  times  each  season.  The  gross  re- 
turns were  $87.29  per  acre  for  the  early  and  $83.80  for  the  late 
irrigated  beets,  without  any  greater  expenditure  of  labor  or  water 
for  the  increased  returns  due  to  early  irrigating. 

Fall  and  Spring  Irrigation;     Plowing 

Fall  or  early  spring  irrigation  will  no  doubt  destroy  most  of  the  lice 
in  the  soil.  However,  if  the  destruction  of  the  lice  is  the  only  reason 

Vol   7*No'fei  U914)y  °f  thC  Sugar"beet  Root-louse-  Pemphigus  betae"  Journal  of  Economic  Entomology. 

56 


Sugar  Beet  Root-louse 

for  this  irrigation  it  is  doubtful  if  the  results  will  warrant  the  use  of  the 
water.  During  the  process  of  plowing  and  working  down  the  seed  bed, 
the  majority  of  the  hibernating  lice  are  destroyed. 

Rotation 

While  quite  a  number  of  lice  live  over  from  season  to  season  in  the 
soil  of  old  beet  fields,  yet  they  are  of  little  importance  as  compared  with 
the  lice  from  the  narrow-leaf  cottonwood  trees  as  a  source  of  infesta- 
tion. For  this  reason  rotation  is  of  very  little  avail  in  preventing 
losses.  The  results  of  a  survey  covering  80,000  acres,  made  in  1916, 
showed  that  83  beets  out  of  100  were  infested  with  root-lice  where  sugar 
beets  were  grown  on  old  beet  ground  and  82  out  of  1 00  where  they  fol- 
lowed all  other  crops.  This  proves  conclusively  that  rotation  will  not 
prevent  root-louse  losses.  The  presence  of  lice  in  the  soil  in  the  spring 
is  no  reason  why  such  fields  should  not  be  planted  to  beets  provided 
they  are  otherwise  fit. 

The  results  of  the  survey  mentioned  above  show  quite  conclusively 
that  the  destruction  of  all  narrow-leaf  cottonwood  trees  within  the  beet 
growing  sections  will  reduce  the  damage  done  by  the  sugar  beet  root- 
louse.  Therefore,  the  cutting  of  these  trees  is  strongly  to  be  recom- 
mended. However,  it  will  not  entirely  free  beet  fields  of  this  pest,  since 
many  lice  reach  them  from  the  foothills  and  canyons. 

DESCRIPTION  AND  LIFE  HISTORY 

Mention  has  already  been  made  of  winged  lice  on  the  beet  roots  in 
the  fall.  During  warm,  sunny  autumn  days  swarms  of  these  little 
winged  lice  leave  the  beet  fields  and  fly  to  the  narrow-leaf  cottonwood 
trees. 

About  every  narrow-leaf  cottonwood  with  the  rays  of  the  sun 
glistening  on  their  wings,  thousands  of  lice  sway  in  and  out  among  the 
branches.  One  by  one  they  alight  to  go  hurrying  up  and  down  as  if 
fearful  lest  the  oncoming  winter  overtake  them  before  suitable  homes 
for  their  young  have  been  found. 

In  deep  crevices  and  under  loose  pieces  of  bark  these  winged  migrants 
from  the  beet  fields  deposit  their  minute,  yellowish  young.  These  are 
of  two  kinds,  tiny  little  females  (Fig.  18,  Plate  II,  Page  13),  and  still 
smaller  males  (Fig.  16,  Plate  II).  (Note  the  minute  representation  of 
the  actual  size  of  these  lice,  shown  at  the  left  of  the  figures.)  Almost 
microscopic  in  size,  mouthless  and  living  but  a  few  days,  their  sole  object 
in  life  is  to  produce  the  solitary  egg  which  each  female  lays.  This  accom- 
plished the  female  dies,  the  male  having  died  shortly  after  mating  took 
place. 

Figure  13,  Plate  II,  Page  13,  is  the  antenna  of  Figure  16,  Plate  II, 
Page  13,  greatly  enlarged. 

The  eggs,  one  of  which  is  shown  very  much  enlarged  (Fig.  17,  Plate 
II),  are  about  ^  of  an  inch  long  and  one-fourth  as  broad.  Snugly 
tucked  away  in  some  crevice  of  the  bark  they  remain  until  the  warm 
days  of  spring  cause  the  buds  to  swell,  when  from  each  egg  a  small,  dark 
louse  (Fig.  2,  Plate  II,  much  enlarged)  emerges.  As  soon  as  hatched 
this  little  louse  starts  in  search  of  an  opening  bud.  When  one  is  found 

57 


Sugar  Beet  Root-louse 

it  crawls  in  among  the  expanding  leaves  and  begins  to  feed  upon  the 
upper  surface  of  one  close  to  the  midrib.  This  feeding  causes  a  depression 
to  form  and  the  leaf  to  turn  light  in  color  (Fig.  1-A,  Plate  II). 

In  the  course  of  a  few  days  this  depression  has  become  a  swelling  on 
the  under  side  of  the  leaf  (Fig.  4,  Plate  II),  which  is  now  entirely  closed 
on  the  upper  side  (Fig.  3,  Plate  II).  In  this  gall,  as  the  swelling  is  called, 
the  little  louse  is  securely  protected  from  inclement  weather  and  the 
sharp-eyed  birds  as  they  flit  among  the  branches.  Both  the  gall  and  the 
louse  increase  in  size  for  some  time,  until  the  former  appears  as  in  Figure 
5,  Plate  II,  and  the  louse,  which  is  called  a  stem-mother,  as  shown  in 
Figure  6,  Plate  II. 

This  rotund  stem-mother  gives  birth  to  several  living  young  daily 
during  the  next  month  or  six  weeks.  If  opened  about  the  middle  of 
June  the  gall  will  be  found  to  contain  many  pale  lice  all  surrounded  by 
a  whitish  substance.  This  waxy  material  is  secreted  by  glands  and 
escapes  through  what  are  called  wax-pores,  which  are  arranged  in  rows 
across  the  body  of  the  insect.  These  appear  as  light,  round  spots  on  the 
back.  (Fig.  6,  Plate  II). 

The  young  of  the  stem-mother  do  not  resemble  her  in  form,  being 
slender  of  body  and  at  first  wingless.  As  they  grow  older  wing  pads 
appear  on  their  shoulders.  After  shedding  their  skins  several  times, 
growing  darker  with  every  succeeding  molt,  the  last  larval  skin  is  shed 
and  a  delicately  winged  louse  (Fig.  7,  Plate  II)  emerges.  The  antenna 
of  this  winged  louse  is  shown  in  Figure  8,  Plate  II. 

About  the  time  the  first  winged  lice  appear  the  mouth  of  the  gall 
begins  to  open.  Through  this  opening  the  winged  lice  escape  and  fly 
or  are  blown  by  the  wind  far  and  wide  among  the  beet  fields,  where  they 
settle  on  the  beets  and  deposit  their  young,  which  immediately  descend 
to  the  ground  and  take  up  their  abode  on  the  beet  roots.  All  the  young 
of  the  winged  migrants  from  the  cotton  wood  trees  are  wingless  and  when 
full  grown  appear  as  shown  in  Figure  9,  Plate  II. 

The  antenna  of  the  wingless  lice  which  are  found  on  the  beet  roots 
is  shown  in  Figures  11  and  12,  Plate  II. 

These  wingless  lice  give  birth  to  still  more  wingless  lice.  This  goes 
on  until  several  generations  and  hundreds  of  lice  have  been  produced  on 
the  beets.  Then  with  the  return  of  fall  some  of  the  lice  on  the  beet  roots 
develop  wing  pads  like  those  of  the  young  of  the  stem-mother  in  the  gall. 
After  acquiring  wings  these  lice  are  known  as  the  fall  migrants. 

These  migrants  return  to  the  narrow-leaf  cottonwoods  and  there 
deposit  their  young.  Thus  we  have  followed  the  lice  from  the  galls  on 
the  cotton  wood  trees  to  the  beet  fields  and  back  again  to  the  cottonwoods. 
Not  all  of  the  lice  become  winged  in  the  fall,  however.  Some  wing- 
less ones  remain  over  the  winter  in  the  soil,  where  they  hibernate  in 
earth-worm  burrows  and  other  openings.  Thus  we  see  that  nature  has 
provided  two  means  of  carrying. the  beet  root-lice  over  the  winter:  the 
hibernating  lice  in  the  soil,  and  the  eggs  in  the  crevices  of  the  cotton- 
wood  bark. 

58 


Sugar  Beet  Root-louse  Sugar  Beet  Nematode 

NATURAL  ENEMIES 

While  in  the  galls  a  bug*  (Fig.  14,  Plate  II,  Page  13)  preys  upon 
the  lice.  In  the  beet  fields  the  little  lady-beetle  l  l  and  its  larva  (Figs. 
10  and  15,  Plate  II,  Page  13)  feed  upon  the  root-lice.  This  larva, 
which  is  not  very  much  larger  than  a  good  sized  louse,  secretes  a  white, 
waxy  substance  with  which  its  body  is  covered,  making  it  resemble  to 
a  remarkable  degree  one  of  the  lice  upon  which  it  feeds.  The  pupa  of 
this  beetle  (Fig.  14,  Plate  VII,  Page  23)  is  surrounded  by  the  cast  larval 
skin  and  white  flocculent  coating. 

The  larvae  or  maggots  of  the  Syrphus-fly  14  (Fig.  13,  Plate  VI,  Page 
21)  do  their  part  in  destroying  this  pest. 

Every  season  large  numbers  of  the  lice  are  killed  by  a  fungous  dis- 
ease.** This  fungus  develops  within  the  lice  and  finally  causes  their 
death.  Were  it  not  for  these  natural  checks  the  damage  caused  an- 
nually by  the  beet  root-louse  would  be  far  greater  than  it  is  now. 

Slender,  yellowish-white  maggots  are  often  seen  among  the  lice  on 
beet  roots.  These  are  the  larvae  of  a  small,  striped  flyj  (Fig.  14,  Plate 
VI,  Page  21).  Recent  investigations  f  show  that  these  maggots  are 
very  effective  in  destroying  the  beet  root-lice.  During  the  latter  part 
of  the  season  small,  oval,  brown  bodies  will  be  seen  among  the  lice  also. 
These  have  often  been  mistaken  for  the  eggs  from  which  the  lice  hatch. 
Instead  of  being  root-louse  eggs  they  are  the  thickened  larval  skins 
within  which  the  maggots  change  into  the  flies  mentioned  above. 


2.     SUGAR  BEET  NEMATODE 

(Figs.  8,  9  and  10,  Plate  III,  Page  15) 

Quite  early  in  the  history  of  the  beet  sugar  industry  in  Europe  it 
was  noticed  that  the  yield  of  sugar  beets  was  steadily  dropping  off  in 
certain  districts.  In  spite  of  the  efforts  of  the  growers  to  maintain  the 
yield  by  using  fertilizers,  and  in  spite  of  their  increasing  knowledge  of 
the  handling  of  the  crop,  the  tonnage  secured  was  so  unsatisfactory  that 
the  growing  of  sugar  beets  was  discontinued  on  many  fields. 

Many  theories  were  advanced  in  explanation  of  this  condition.  The 
most  prevalent  and  generally  accepted  of  these  attributed  the  trouble 
to  an  exhaustion  of  the  mineral  plant  foods  of  the  soil. 

It  was  noticed  that  those  fields  where  beets  had  been  grown  con- 
tinuously for  several  years  were  most  affected.  This  led  the  Germans  to 
give  the  name  "Riibenmiidigkeit, "or  "beet  weariness, "  to  this  malady. 

A  German  scientist  named  Klihn  was  first  to  associate  the  soil  in- 
habiting eel  worm  or  nematode  (Heterodera  schachtii)  with  this  trouble. 

The  sugar  beet  nematode  so  far  has  been  found  only  in  a  few  well 
defined  localities  within  the  territory  in  which  The  Great  Western  Sugar 
Company  operates. 

*Authocoris  melanocerus. 
**Emt>usa  aphidis. 
IChlorobisca  glabra. 

tJ.  R.  Parker,  "Life  History  and  Habits  of  Chlorofiisca  glabia  Meign.."  Journal  of  Economic  Ento- 
mology, Vol.  XI,  No.  4   (1918).       ' 
("-»«)  See  explanation  of  "Reference  Figures."  page  2. 

59 


Sugar  Beet  Nematode 


Fig.  6.     A  Sugar  Beet  infested  with  Sugar  Beet  Nematodes.    The  white  bodies  of 
the  female  nematodes  can  be  seen  clinging  to  the  rootlets. 


T  A  Sugar  Beet  affected  with  Curly-top,  showing  the  characteristic  dense  mass  of  rootlets.    (After  C.  0. 

Townsend.  Farmers'  Bulletin  No.  122,  U.  S.  Department  of  Agriculture.) 


Sugar  Beet  Nematode 
NATURE  OF  INJURY 

The  young  sugar  beet  nematodes  search  out  a  beet  root,  and  by 
piercing  it  with  their  strong  spear-like  mouth  parts,  embed  themselves 
within  the  tissue.  They  then  begin  to  feed  upon  the  juices  of  the  beet. 

Effect  on  Roots 

The  presence  of  the  nematodes  causes  an  irritation  of  the  roots. 
Because  of  this  irritation,  and  because  the  sap  is  consumed  by  the  nema- 
todes, the  roots  are  unable  to  carry  the  water  and  plant  food  to  the  beet, 
and  the  growth  of  the  plant  is  interferred  with. 

In  an  attempt  to  overcome  this  trouble  the  beets  send  out  many 
new  rootlets  from  the  root  seams  at  each  side  of  the  main  root.  In 
Europe  these  beets  have  been  called  "bearded  roots"  or  "hunger  roots." 
Such  beets  (Fig.  6,  Page  60)  resemble  the  "whiskered  beets"  suffering 
from  a  severe  attack  of  the  disease  known  as  "Curly-top"  (Fig.  7,  Page 
60). 

If  carefully  removed  from  the  soil,  the  rootlets  of  infested  beets 
will  have  many  minute,  pearly-white  bodies  clinging  to  them  (Fig.  9, 
Plate  III,  Page  15).  These  are  the  mature  female  nematodes. 

In  extreme  cases  the  weakened  roots  become  infested  with  fungi  and 
bacteria  which  cause  them  to  rot  or  the  plants  die  because  of  lack  of 
nourishment. 

Effect  on  Leaves 

The  presence  of  nematodes  becomes  apparent  in  the  appearance  of 
the  leaves  as  the  season  advances.  The  foliage  of  the  infested  plants 
turns  light  in  color,  becoming  a  yellowish  green,  or  they  have  the  dull, 
gray-green  color  of  beets  suffering  from  lack  of  water.  The  leaves  wilt 
and  finally  lie  flat  on  the  ground,  failing  to  recover  during  the  night. 
The  outer  ones  finally  die.  The  growth  of  the  inner  leaves  is  seriously 
interfered  with,  and  in  severe  cases  they  die  also.  If  the  beet  does  not 
succumb  to  the  attack,  the  new  leaves  produced  fail  to  attain  normal 
size  and  are  often  much  curled  and  distorted.  Late  in  the  season,  beets 
which  have  survived  the-  attack  are  often  a  darker  green  than  their 
uninfested  neighbors. 

Effect  on  Sugar  Content 

Not  only  is  the  size  of  the  roots  and  leaves  of  the  beets  affected 
but  the  sugar  content  is  greatly  reduced  as  a  result  of  the  nematode 
attack.  For  example,  moderately  infested  beets  contained  11.35% 
sugar  and  badly  infested  ones  only  8.4%  in  a  field  where  healthy  plants 
had  a  sugar  content  of  14.9%.* 

HOW  NEMATODES  SPREAD 
By  Their  Own  Movements 

Sugar  beet  nematodes  have  the  power  of  increasing  by  their  own 
movements  the  area  infested.  In  certain  stages  of  their  development 
and  under  favorable  conditions  they  can  travel  considerable  distances 
in  the  soil.  The  ravages  of  this  pest  have  been  known  to  be  extended 
from  50  to  75  feet  each  season  in  this  way.* 

*Harry  B.  Shaw.  "Control  of  the  Sugar-Beet  Nematode."  Farmers'  Bulletin  No.  772.  U.  S.  Depart- 
ment of  Agriculture  (1916). 

61 


Sugar  Beet  Nematode 

Carried  by  Irrigation  Water 

Irrigation  water  passing  over  infested  areas  carries  many  nematodes 
to  uninfested  localities  with  the  soil  washed  away  from  these  areas. 

The  use  of  factory  waste  water  for  irrigation  purposes  has  resulted 
in  spreading  this  pest  over  large  areas  in  those  localities  where  the  nem- 
atodes exist. 

Carried  by  Implements,  People  and  Live  Stock 

Nematode  infested  soil  is  often  carried  from  infested  to  uninfested 
fields  on  the  farm  implements  used  in  their  cultivation. 

The  wagons  used  in  hauling  a  crop  from  infested  fields  or  in  hauling 
manure  onto  such  fields  often  carry  the  nematodes  to  other  fields. 

Work  animals  or  stock  allowed  to  run  on  infested  land,  as  well  as 
people,  spread  this  pest  by  carrying  the  eel  worm  in  the  soil  clinging  to 
their  feet. 

In  Manure  of  Animals 

The  sugar  beet  nematode  does  not  pass  through  the  digestive  organs 
of  sheep  alive.  There  seems  to  be  no  evidence  that  this  is  true  of  other 
farm  animals.  It  is  therefore  quite  possible  that  nematodes  may  be 
carried  in  the  manure  of  other  animals,  and  if  beet  tops  on  infested  land 
are  to  be  pastured,  sheep  should  be  used  for  this  purpose. 

METHODS  OF  CONTROL 

The  fact  that  the  sugar  beet  nematode  is  a  really  formidable 
pest,  if  allowed  to  spread,  cannot  be  too  strongly  impressed  upon 
the  minds  of  all  beet  growers,  especially  as  it  occurs  in  damaging 
numbers  in  several  beet  growing  sections  of  the  United  States, 
including  a  small  area  in  Colorado. 

Since  there  are  no  known  methods  of  entirely  freeing  the  soil  of 
nematodes  which  can  be  used  in  field  practice,  the  adoption  of  proper 
precautions  to  prevent  their  introduction  into  new  fields  is  of  the  greatest 
importance.  Once  this  eelworm  is  established,  the  prevention  of  its 
spread  is  no  less  important  than  the  establishing  of  a  system  of  crop 
rotation  which  will  check  its  multiplication. 

How  to  Prevent  Spread  of  Nematodes 

(1)  No  waste  water  should  be  allowed  to  run  from  infested  to  un- 
infested fields. 

(2)  In  infested  areas,  factory  waste  water  should  not  be  used  for 
irrigation  purposes  unless  first  properly  treated  with  lime. 

(3)  All  implements  used  in  working  infested  land  should  be  very 
carefully  cleaned  by  removing  all  soil  from  them  before  they  are  used  in 
uninfested  fields.     This  includes  the  cleaning  of  wagon  wheels. 

(4)  The  feet  of  persons  and  work  animals  should  be  thoroughly 
cleaned  before  going  from  infested  to  uninfested  fields. 

(5)  Live  stock  should  not  be  allowed  to  run  on  infested  land  unless 
it  is  to  be  confined  there  until  removed  to  market. 

(6)  Beet  tops  from  infested  land  should  not  be  removed  but  should 
be  pastured  on  the  land  where  grown. 

.(7)  The  manure  of  animals  fed  on  beet  tops  from  infested  land 
should  not  be  used  on  uninfested  land. 

62 


Sugar  Beet  Nematode 

How  to  Check  Multiplication  of  Nematodes 
Field  Surveys 

All  suspected  fields  should  be  thoroughly  examined,  so  that  the 
exact  location  and  extent  of  infested  areas  may  be  known.  That  such 
surveys  of  suspected  lands  be  made  is  of  the  greatest  importance. 

Local  Treatment 

If  the  infested  areas  are  small,  local  treatment  may  be  all  that  is 
necessary.  All  plants  on  the  area  should  be  pulled,  together  with  those 
from  a  strip  several  feet  wide  all  around  it.  These  should  be  destroyed 
by  burning  on  the  spot. 

A  trench  about  one  foot  deep  and  one  foot  wide  should  then  be  dug 
around  the  infested  spot  and  this  filled  with  quick-lime.  The  surface 
of  the  infested  area  should  be  covered  with  lime  an  inch  or  two  deep  and 
this  thoroughly  mixed  with  the  soil.  Frequent  mixing  of  the  limed  soil 
will  add  to  the  effectiveness  of  the  treatment. 

Pasturing  with  Sheep 

Pasture  the  beet  tops  grown  on  infested  land  to  sheep,  rather  than  to 
other  stock,  as  the  nematode  in  the  tops  eaten  will  thus  be  destroyed,  and 
will  not  be  returned  to  the  soil  through  the  manure. 

Rotation 

The  sugar  beet  nematode  infests  the  roots  of  many  weeds  and  cul- 
tivated crops.  The  following  list  of  plants  known  to  be  subject  to  attack 

is  taken  from  Farmers'  Bulletin  No.  772  of  the  U.  S.  Department  of 
Agriculture. 

Alfalfa  Dandelions  Pinks 

Allseed  Foxtail,  Green  Potatoes 

Barley  Hemp  Radishes 

Beans,  Dwarf  Pea      Hops  Rape 

Beans,  Lima  •  Kale  Rutabaga 

Beets,  Garden  Kohl-rabi  Rye 

Beets,  Sugar  Lentils  Sorghum 

Cabbage  Lupine,  Yellow  Spinach 

Cabbage,  Chinese       Meadow-grass,  Annual  Sunflower 

Cauliflower  Meadow  Oat-grass,  Tall  Timothy 

Celery  Mustard  Turnips 

Clover,  Crimson         Oats  Vetch 

Clover,  White  Parsnips  Wheat 

Corn  Peas,  Garden 

Cress  Peas,  Sweet 

In  the  above  mentioned  bulletin  the  author  lists  the  following  crops 
as  being  available  for  Colorado  and  neighboring  states  for  rotation  on 
infested  land : 


Cow  Peas 

Soy  Beans 

Sweet  Clover 

Rye 

The  Millets 

Tomatoes 


Asparagus 

Lettuce 

Cantaloupe 

Barley 

Wheat 

Cucumbers 


Potatoes 
Potatoes  are  often  slightly  injured. 

63 


Sugar  Beet  Nematode  Root-knot  Nematode  or  GaUworm 

DESCRIPTION  AND  LIFE  HISTORY 

In  the  course  of  its  development  the  sugar  beet  nematode  passes 
through  four  forms  or  stages:  the  egg,  two  larval  stages,  and  the  adult. 

The  Egg 

Each  adult  female  produces  from  300  to  400  eggs.     These  are  color- 
less and  broadly  oval  or  kidney-shaped.     They  are  extremely  small, 
being  only  about  s^0  °f  an  incri  l°nS- 
The  Larval  Stages 

The  young  nematodes,  or  larvae,  are  very  active,  threadlike  creatures. 
Being  colorless  and  almost  microscopic  in  size,  they  are  seldom  noticed 
in  the  field. 

It  is  in  the  first  larval  stage  that  the  nematodes  enter  the  tissue  of 
the  beet  roots.  The  first  larval  skin  is  cast  shortly  after  entering  the 
beet  and  the  larva  takes  on  a  more  robust  form. 

The  Adult 

With  a  second  molt  the  nematode  becomes  an  adult  male  (Fig.  10, 
Plate  III,  Page  15),  or  female  (Fig.  8,  Plate  III,  Page  15). 

% 

The  Brown-cyst  Stage 

As  cold  weather  approaches  or  conditions  become  unfavorable  for 
the  development  of  the  females,  certain  individuals  pass  into  a  resting  or 
preservation  stage  which  is  known  as  the  brown-cyst  stage. 

In  the  cyst  form  the  female  passes  the  winter  or  the  period  of  un- 
favorable conditions  protecting  the  eggs  until  conditions  become  favor- 
able for  further  development.  With  the  change  of  conditions  the  eggs 
begin  to  hatch.  They  do  not  all  hatch  at  once,  however,  but  may  con- 
tinue to  do  so  ror  long  periods  that  may  extend  over  several  years. 

3.     ROOT-KNOT  NEMATODE  OR  GALLWORM 

This  nematode,  which  is  very  closely  related  to  the  sugar  beet  nem- 
atode, seriously  interferes  with  the  growing  of  sugar  beets  in  some 

localities. 

This  nematode  has  been 
found  in  the  Sterling,  Brush, 
Ft.  Morgan  and  Scottsbluff 
districts. 

NATURE  OF  INJURY 

The  roots  of  infested  plants 
present  a  very  characteristic 
appearance.  The  presence  of 
the  females  and  larvae  in  a 
root  is  indicated  by  irregular 
swellings  (Fig.  8,  Page  64), 

Fig.  8.     Small  Sugar  Beets  infested  with  the 

Root-knot  Nematode.     The  bead-like  swellings  Caused    by    the    irritation  Set 
on  the  small  roots  and  the  enlargements  of  the  ,          ,  , 

mam  root  are  caused  by  the  nematodes.  Up   by   these   eelwormS. 

64 


Root-knot  Nematode  or  Gallworm 

METHODS  OF  CONTROL 
Prevent  Spread  of  Nematodes 

In  order  to  prevent  the  spread  of  this  pest,  the  same  precautions 
should  be  observed  as  in  the  case  of  the  sugar  beet  nematode  (See  page  62) . 

Potatoes  grown  on  infested  land  should  not  be  used  for  seed,  as  the 
nematodes  pass  the  winter  within  the  tubers. 

Such  plants  as  tomatoes,  cabbage,  strawberries,  kale,  sweet  potatoes, 
asparagus  and  horse-radish  should  not  be  taken  from  infested  soil  and 
transplanted  in  nematode  free  fields. 

Nematode  Eradication 

There  is  no  practical  means  of  entirely  eradicating  the  gallworm  in 
large  fields.  In  the  case  of  hotbeds  and  greenhouses  soil  fumigants  can 
be  used,  but  these  are  too  expensive  for  field  use. 

Rotation 

The  most  practical  method  of  reducing  the  numbers  of  nematodes 
is  to  rotate  with  such  crops  as  are  not  attacked.  Mr.  C.  S.  Scofield* 
gives  the  following  list  of  crops  as  suited  for  planting  on  infested  soil : 

Barley  Sorghum 

Oats  Milo 

Wheat  Kafir 

Rye  Timothy 

Corn  Red  Top 

The  value  of  growing  the  resistant  crops  named  above  is  strikingly 
illustrated  by  the  results  of  a  survey  of  five  large  areas  in  which  all  sugar 
beet  fields  infested  with  the  root-knot  nematode  were  located  and  a  record 
secured  of  the  crop  grown  on  all  fields,  both  infested  and  uninfested  the 
year  previous.  It  was  found  as  the  per  cent  of  resistant  crops  grown 
increased,  the  per  cent  of  infested  beet  fields  decreased.  These  figures 
are  given  in  the  following  table: 

%  of  total 

Total  fields      %  of  total     growing  nematode 
Area        examined          infested  resistant  crops 

A  366  58.47  5.19 

B  480  51.87  6.66 

C  768  28.77  9.77 

D  671  2.08  12.09 

E  676  1.03  28.06 

LIFE  HISTORY 

During  the  greater  part  of  their  lives  these  worms  remain  embedded 
within  the  tissue  of  the  roots  of  their  host  plants. 

Upon  reaching  maturity  the  fertilized  females  begin  the  production 
of  eggs.  Some  of  these  hatch  within  the  body  of  the  parent,  the  young 
ultimately  escaping  into  the  surrounding  tissue  of  the  host  plant.  Others 
are  laid  at  the  rate  of  ten  or  fifteen  daily.* 

*"The  Nematode  Gallworm  on  Potatoes  and  Other  Crop  Plants  in  Nevada."  Circular  No.  91,  Bureau 
of  Plant  Industry.  U.  S.  Department  of  Agriculture  (1912). 

65 


Root-knot  Nematode  or  Gallworm 

Shortly  after  the  larvae  hatch  they  escape  from  the  root  of  the  host 
plant  and  spend  a  time  in  the  soil.  Soon  they  search  out  the  root  of  a 
suitable  plant  and  burrow  into  it,  where  they  feed  upon  its  sap,  causing 
the  characteristic  swellings  already  mentioned. 

The  nematode  gallworm  lives  from  season  to  season  embedded  in 
the  tissue  of  the  host  plant  either  in  the  egg  or  larval  stage.  The  life  of 
the  adult  is  only  a  few  weeks  under  favorable  conditions. 

Plants  and  crops  subject  to  severe  infestation  which  should  never 
be  planted  on  infested  land  :* 

Beet  Pumpkin  Cowpea 

Carrot  Potato  Rape 

Celery  Salsify  Soy  bean 

Cucumber  Squash  Cat'alpa 

Egg  plant  Tomato  Cherry 

Lettuce  Watermelon  Elm 

Muskmelon  Clover  Peach 

Plants  subject  to  attack  but  not  seriously  injured  by  nematode 
gallworms:  These  should  not  be  planted  on  infested  land  as  they  will 
serve  to  keep  the  worms  alive.* 

Alfalfa  Cauliflower  Kale 

Vetch  Garden  pea  Onion 

Sweet  clover  Horseradish  Radish 

Asparagus  Strawberry  Spinach 

Cabbage  Lima  bean  Sweet  potato 

Crops  suited  for  planting  on  infested  land  :* 

Barley  Corn  Kafir 

Oats  Sorghum  Timothy 

Wheat  Milo  Red  top 
Rye 


*Q  S.  Scofield,  "The  Nematode  Gallworm  on  Potatoes  and  Other  Crop  Plants  in  Nevada."  Circular 
No.  91.  Bureau  of  Plant  Industry.  U.  S.  Department  of  Agriculture  (1912). 


66 


Leaf -eating  Caterpillars  Sugar  Beet  Webworm 

CHAPTER  III 


LEAF  FEEDERS 

Either  because  they  feed  exposed  to  the  view  of  the  most  casual 
observer  or  because  their  work  is  such  as  to  attract  general  attention, 
the  leaf-feeding  insects  are  much  more  universally  known  to  the  layman 
than  the  root-feeding  insects.  In  a  general  way  the  methods  of  controlling 
this  class  of  insects  are  common  knowledge  also.  However,  this  knowl- 
edge is  of  a  superficial  nature;  that  is,  it  is  general  instead  of  specific. 
This  lack  of  knowledge  of  the  particular  insect  involved  has  led  to  much 
waste  of  money,  energy  and  material,  either  because  the  wrong  remedy 
has  been  applied  or  the  right  one  was  not  applied  in  the  correct  way  or 
at  the  right  time. 

A.     BITING  LEAF  FEEDERS 

(Caterpillars,  Beetles,  Grasshoppers,  Crickets,  Leaf-miners) 

1.     LEAF-EATING  CATERPILLARS 

The  young  of  moths  or  millers  and  butterflies  are  known  by  the 
general  name  of  caterpillars.  In  size,  shape,  color  and  body  covering 
they  differ  greatly  in  different  species. 

Some  are  but  a  fraction  of  an  inch  in  length,  while  others  attain  a 
length  of  six  or  seven  inches.  For  the  most  part  caterpillars  are  cylindri- 
cal, being  several  times  as  long  as  thick.  Some  are  grub-like  in  form  and 
others  resemble  dead  leaves  or  twigs  in  shape  and  color.  The  bodies  of 
many  are  bare,  those  of  others  are  covered  with  long  hairs.  In  some 
species  these  hairs  are  connected  with  poison  glands.  If  these  cater- 
pillars come  in  contact  with  the  bare  hands  or  face  the  sensation  is  very 
similar  to  that  caused  by  the  sting  of  nettles,  only  more  severe.  Some 
caterpillars  are  really  formidable  in  appearance  because  their  bodies  are 
covered  with  large  .spines  or  spine  covered  tubercles. 

In  the  kinds  of  food  eaten,  caterpillars  are  as  variable  as  in  shape, 
size  or  color.  Some  bore  in  the  wood  of  trees,  others  feed  upon  hair, 
wool,  horn  and  like  substances.  A  few  feed  upon  scale  insects  and  the 
larvae  of  borers.  Several  species  attack  growing  fruits,  while  others 
destroy  stored  fruits  and  grains.  The  species  with  which  we  are  most 
concerned,  and  which  are  discussed  in  the  following  pages,  feed  upon  the 
leaves  of  plants.  Among  this  class  are  to  be  found  some  of  the  worst 
enemies  of  cultivated  crops. 

(a)     SUGAR  BEET  WEBWORM 

(Figs.  3,  4,  5,  6,  8,  9,  10,  1 1,  Plate  V,  Page  19) 

The  sugar  beet  webworm  is  one  of  the  most  destructive  leaf-eating 
insects  attacking  the  sugar  beet.  Like  many  of  our  most  injurious  insect 
pests,  it  was  introduced  into  this  country  from  the  Eastern  Hemisphere, 
appearing  first  on  the  Pacific  coast.  In  1869  it  damaged  beets  in  Utah. 

67 


Sugar  Beet  Webworm 

Since  that  time  it  has  spread  over  the  entire  sugar  beet  growing  areas  of 
the  country. 

The  worst  outbreaks  of  webworms  which  have  occurred  in  the  ter- 
ritories in  which  The  Great  Western  Sugar  Company  is  operating  took 
place  in  1918  and  1919.  During  the  season  of  1918,  the  June  and  August 
broods  both  caused  great  damage.  Some  fields  were  injured  by  both 
broods. 

An  accurate  statement  of  the  acres  damaged  in  1918  and  the  degree 
of  damage  was  reported  by  the  fieldmen  of  The  Great  Western  Sugar 
Company.  These  reports  show  that  31,000  acres  were  injured.  The 
first  brood  injured  5,500  acres  and  the  second  25,500  acres.  Over  7,000 
acres  were  damaged  to  the  extent  of  two  tons  per  acre,  over  7,000  acres 
to  the  extent  of  one  ton  per  acre  and  nearly  15,000  acres  to  the  extent  of 
J  ton  per  acre.  The  total  loss  to  the  growers  and  the  industry  was  not 
less  than  26,450  tons  of  beets.  These  at  $10.00  per  ton,  the  price  in  1918, 
represents  a  money  loss  of  $264,500.  Over  16,000  acres  were  sprayed 
with  Paris  green  at  the  average  rate  of  4  pounds  per  acre,  and  much  loss 
thus  prevented.  This  required  84,000  pounds  of  Paris  green,  much  of 
which  was  furnished  the  growers  at  a  reduced  cost  per  pound  by  The  Great 
Western  Sugar  Company. 

This  loss  could  have  been  very  much  more  reduced  if  all  growers  had 
realized  in  time  that  there  was  danger  and  had  had  themselves  properly 
prepared.  Too  late  spraying  was  responsible  for  much  of  the  loss. 

As  this  bulletin  goes  to  press  the  campaign  against  the  first  brood 
of  1919  is  drawing  to  a  close.  This  brood,  which  is  the  largest  known  in 
the  history  of  sugar  beet  growing  in  the  United  States,  covered  practically 
all  beet  growing  areas  in  Colorado,  Nebraska,  Montana  and  Wyoming. 

In  order  to  assist  the  growers  in  combating  it  The  Great  Western 
Sugar  Company  purchased  several  hundred  traction  sprayers  and  dis- 
tributed about  700,000  pounds  of  Paris  green  in  its  territories.  Had  it 
not  been  for  this  assistance  the  loss  to  the  growers  would  have  far  exceeded 
that  caused  by  both  broods  of  1918. 

NATURE  OF  INJURY 

Webworms  injure  sugar  beets  by  destroying  the  leaves.  This  re- 
tards the  growth,  thus  reducing  the  yield  and  sugar  content.  All  other 
things  being  equal,  the  loss  is  quite  proportional  to  the  loss  in  leaves. 
The  greater  the  amount  of  leaf  surface  destroyed,  the  greater  the  loss. 
On  the  other  hand,  the  losses  depend  somewhat  upon  the  time  of  season 
when  the  damage  is  done,  also  upon  the  weather  condition  immediately 
after  it  is  done. 

Small  beets  may  be  killed  outright  if  the  leaf  surface  is  so  small  that 
the  worms  attack  the  crowns.  Larger  beets  may  have  their  leaves 
entirely  eaten  off  but  recover  by  putting  out  new  leaves.  (See  Fig.  9, 
Page  69,  and  Fig.  10,  Page  70.) 

The  first  indications  that  a  crop  may  be  injured  by  the  sugar  beet 
webworm  is  the  appearance  of  the  moths  (Fig.  11,  Plate  V,  Page  19)  in 
the  field.  These  moths  are  active  and  easily  disturbed  during  the  day. 
When  present  they  will  be  noticed  flying  ahead  of  the  cultivator  or  of 
one  walking  through  the  field.  Their  flights  are  short  and  jerky  and  they 
usually  alight  on  the  under  side  of  a  leaf  or  on  the  ground.  Catch  one 

68 


Sugar  Beet  Webworm 

or  the  moths  and  compare  it  with  the  figure.  If  it  is  the  same  then  look 
for  the  eggs,  continuing  to  do  so  for  several  days.  Call  the  attention 
of  the  Sugar  Company's  fieldman  to  the  moths  and  get  his  advice. 

The  eggs  will  be  found  on  the  under  side  of  the  beet  leaves,  on  lamb's- 
quarters  or  on  Russian  thistle  if  these  weeds  are  growing  in  the  field.  Of 
a  pearly-white  color  and  about  the  size  of  a  small  pin-head,  they  are  not 
easily  seen  unless  careful  search  is  made  for  them. 


Fig.   9.     Sugar  Beet  badly  damaged  by   Webworm.s 

Even  though  no  eggs  can  be  found,  do  not  assume  that  all  danger  is 
past.  Often  the  eggs  are  overlooked  and  the  first  indication  you  have 
that  your  crop  is  infested  is  the  presence  of  newly  hatched  worms  hang- 
ing from  the  under  side  of  the  leaves  by  a  short  web.  These  can  best 
be  seen  by  getting  down  near  the  ground  and  looking  up  and  down  the 
rows.  Both  the  worms  and  web  are  light  colored  and  not  very  easily 
seen  unless  the  light  is  just  right.  Looking  away  from  the  sun  makes 
them  more  easily  discerned. 

Picking  leaves  at  random  over  a  field  and  noting  the  number  of  eggs 
or  young  worms  present  is  a  very  good  way  of  estimating  the  possibility 
of  damage  in  the  near  future.  Great  care  must  be  taken  not  to  under- 
estimate this  possibility,  however.  One  or  two  worms  or  eggs  on 
one-half  to  three-fourths  of  the  leaves  indicate  the  presence  of  enough 
worms  seriously  to  injure  the  crop  later.  As  some  of  the  worms  drop 
from  the  leaves  when  they  are  broken  off,  the  worms  seen  do  not  represent 
all  present. 

69 


Sugar  Beet  Webworm 

Very  often  a  few  eggs  in  one  part  of  a  field  indicate  that  in  some 
other  portion  there  are  many  more.  Not  infrequently  the  moths  lay  eggs 
by  the  hundreds  and  thousands  over  a  very  small  area.  This  is  quite 
as  apt  to  be  in  the  center  of  the  field,  or  at  least  some  distance  from  the 
border,  as  near  the  edge  of  the  field.  All  weedy  spots  should  be  carefully 
examined  and  the  weeds  removed  as  soon  as  possible,  as  these  are  often 
the  places  where  the  injury  starts  and  spreads  to  the  entire  field. 

It  is  hard  for  a  person  who  has  not  seen  a  severe  outbreak  of  web- 
worms  to  realize  that  what  appears  to  be  but  a  few  small  worms  is  capable 
of  causing  the  loss  of  several  dollars  worth  of  beets.  This  fact  has  been 
the  cause  of  a  great  deal  of  the  loss  in  the  past. 

If  eggs  or  young  worms  are  found  it  is  time  to  get  your  spray 
machine  out,  or  your  neighbor's  if  you  do  not  have  one  of  your 
own,  and  provide  a  supply  of  Paris  green  ready  to  apply  as  soon  as 
the  eggs  begin  to  hatch. 

As  the  young 
worms  feed  entirely 
on  the  under  side 
of  the  leaves  for 
several  days  after 
they  leave  the  eggs 
and  do  not  eat  away 
the  upper  surface, 
their  presence  is  not 
suspected,  many 
times,  until  they 
are  so  far  developed 
that  much  damage 
is  done  before  they 
can  be  controlled. 

When  fi  rs  t 
hatched  the  worms 
are  so  small  that 
their  capacity  for 
doing  damage  is 
limited.  As  they 
increase  insize  their 
appetites  become 

The  rapidity  with  which  they  will  completely  strip  a 
beet  field  of  leaves  is  almost  beyond  belief.  Each  worm  will  eat  several 
times  its  own  weight  of  beet  leaf  every  day.  So  rapid  is  their  work  that 
although  there  is  no  apparent  injury  today,  tomorrow  or  the  next  day 
large  spots  in  the  field  may  be  completely  defoliated. 

These  spots  very  often  occur  in  the  center  of  the  field,  thus  they  are 
overlooked  unless  it  happens  that  the  grower  is  cultivating  or  irrigating 
at  the  time. 


Fig.  10.     Suga 

almost  insatiable. 


Beets  badly  damaged  by  Webwor 


70 


Sugar  Beet  Webworm 

Careful  watch  should  be  kept  of  the  beets  during  the  last  half 
of  June  and  the  latter  part  of  July  and  early  August.  Examine 
the  under  side  of  the  beet  leaves  every  day  or  so. 

If  young  worms  are  present  small  pits  will  be  eaten  into  the  lower 
surface  of  the  leaves.  In  case  such  pits  occur  the  little  whitish-yellow 
worms  should  be  found  not  far  away.  If  the  worms  are  several  days  old 
they  will  be  greenish  in  color,  appearing  more  like  the  full  grown  worm 
(Fig.  6,  Plate  V,  Page  19).  At  this  age  they  will  be  found  on  both  sides 
of  the  leaves.  The  edges  of  the  leaves  will  be  eaten  away,  leaving  them 
ragged,  or  the  entire  leaf  will  be  eaten  with  the  exception  of  the  heavy 
veins.  The  young  leaves  at  the  heart  of  the  beet  are  usually  the  last 
eaten. 


Fig.  11.     Field  of  Sugar  Beets  showing  Work  of  the  Sugar  Beet  Webworm.     Bare 
areas  were  weedy  when  eggs  were  laid.     Balance  of  field  was  free  from  weeds. 

Sometimes  the  worms  will  be  concealed  in  webs  spun  over  the  leaf, 
usually  near  its  base.  In  case  small,  roundish,  dark  colored  pellets 
are  seen  on  the  leaves,  a  webworm  or  some  other  leaf-eating  caterpillar 
is  present.  The  culprit  should  be  located  and  his  identity  established. 

METHODS  OF  CONTROL 
Destruction  of  Weeds 

The  sugar  beet  webworm  moth  shows  a  particular  liking  for  lamb's- 
quarters  and  Russian  thistle  as  plants  on  which  to  deposit  its  eggs.  For 
this  reason  if  these  weeds  are  abundant  in  a  field  of  beets  the  crop  is  apt 
to  be  damaged  by  webworms  if  the  moths  are  at  all  numerous  in  the 
vicinity.  Volunteer  alfalfa  is  also  a  menace  to  the  crop. 

The  effect  of  allowing  weeds  to  grow  in  a  crop  of  beets  is  strikingly 
illustrated  by  the  cut  on  page  71  (Fig.  11). 

71 


Sugar  Beet  Webworm 

At  blocking  and  thinning  time  this  field  was  quite  free  of  weeds 
except  a  strip  running  entirely  across  the  picture  from  right  to  left 
and  indicated  by  the  bare  spots  at  either  side.  The  hand  labor  began 
thinning  before  the  webworms  appeared,  cleaning  out  the  rows,  including 
the  center  portion  of  the  weedy  strip,  but  leaving  the  weeds  in  the  sec- 
tions at  each  end  represented  by  the  bare  spots.  They  then  moved  to 
another  part  of  the  field.  In  the  meantime  the  webworm  moths  deposited 
thousands  of  eggs  on  the  weeds  left. 

When  the  labor  returned  to  this  part  of  the  field  both  the  weeds  and 
the  beets  among  them  were  stripped  of  their  leaves.  The  beets  on  that 
part  of  the  weedy  strip  that  had  been  cleaned  out  earlier  were  not  dam- 
aged. The  worms  were  just  moving  to  the  beets  surrounding  the  weedy 
patches,  but  a  thorough  application  of  Paris  green  applied  according  to 
the  instructions  given  later  killed  them  and  no  further  damage  was  done. 

Furrow  Trap 

Weedy  ground  bordering  a  beet  field  is  very  often  as  bad  as  weeds  in 
the  field.  As  soon  as  the  worms  have  destroyed  the  weeds  on  which  they 
hatch,  hunger  compels  them  to  search  for  food.  At  such  times  they 
travel  in  armies,  devouring  whatever  green  thing  comes  in  their  way. 
A  furrow  plowed  about  the  field  and  a  small  stream  of  water  kept  running 
in  it  will  prevent  the  advancing  worms  from  entering  it.  Newly  cut 
alfalfa  thoroughly  sprayed  with  Paris  green  placed  in  the  path  of  the 
oncoming  army  will  destroy  the  worms  by  thousands. 

Irrigation 

In  case  both  the  moths  and  worms  escape  your  observation  and 
you  are  not  aware  that  your  crop  is  being  damaged  until  a  large  por- 
tion of  the  leaves  are  eaten,  the  damage  can  sometimes  be  lessened  by 
applying  water  to  the  crop,  thus  stimulating  the  growth  of  beets.  This 
is  especially  true  if  the  season  is  dry. 

Poison 

After  the  webworms  have  appeared  in  a  field  the  only  way  to  prevent 
loss  is  to  kill  them  by  spraying  with  some  poison.  Paris  green  seems 
best  for  this  purpose.  Being  prepared  for  quick  action  as  soon  as 
the  proper  time  comes  to  begin  the  fight  is  extremely  important. 
Have  all  your  forces  mustered,  all  equipment  in  working  order 
and  a  good  supply  of  Paris  green  on  hand.  When  the  time 
comes  strike  and  strike  hard,  working  as  rapidly  as  possible. 

The  most  vulnerable  period  of  the  webworm's  life  is  during  the  first 
few  days  after  it  leaves  the  egg.  There  are  two  reasons  why  this  is  the 
best  time  to  fight  this  enemy  of  the  beet  crop : 

(1)  If  killed  when  young  the  worms  will  not  have  time  to  do  much 
damage,  which  means  that  they  will  not  eat  as  much  leaf  before 
dying  as  they  would  if  they  were  older. 

(2)  It  requires  less  poison  to  kill  the  young  worms. 

However,  do  not  think  that  because  less  poison  is  needed  to 
kill  the  young  worms  that  less  should  be  used,  for  this  is  not  the 
case.  Too  diluted  a  poison  will  mean  an  unnecessary  consumption  of 
leaves  to  bring  about  the  death  of  the  worms. 

72 


Sugar  Beet  Webworm 

Paris  green  gives  more  satisfactory  results  and  works  more  quickly 
than  any  poison  yet  used  for  killing  sugar  beet  webworms. 

In  using  this  poison  apply  not  less  than  4  pounds  per  acre. 
(For  the  method  of  determining  the  amount  of  poison  applied  per  acre, 
see  "Test  Your  Sprayer"  on  page  35). 

A  good  type  of  traction  sprayer,  when  properly  adjusted,  should 
apply  about  50  gallons  of  water  to  the  acre.  If  too  little  water  is  used 
the  beet  plants  are  apt  to  be  burned ;  if  too  much  is  used  much  poison 
is  wasted. 

Arsenate  of  lead  acts  very  much  more  slowly  than  Paris  green, 
therefore  seldom  gives  satisfactory  results.  This  poison  can  be  secured 
in  two  forms,  dry  and  as  a  paste  containing  50%  water.  These  are  not 
recommended  except  in  case  Paris  green  cannot  be  secured.  When 
used,  not  less 
than  8  pounds 
of  the  dry  or  16 
pounds  of  the 
paste  should  be 
applied  per  acre. 
If  the  worms  are 
large,  arsenate  of 
lead  is  not  recom- 
mended, as  it  acts 
too  slowly. 

Best  results  are 
only  secured 
when  the  poison 
is  applied  with  a 
pressure  sprayer 
which  will  main- 
tain a  pressure  of 
80  pounds.  Such 
a  machine  pro- 
duces the  fine 
mist-like  spray 
which  is  necessary 
in  order  to  place 
the  poison  on  the 
under  side  of  the 
leaves. 

The  effect  of  spraying  at  the  proper  time,  with  the  proper  equipment 
and  with  the  proper  amount  of  Paris  green,  is  clearly  shown  in  Figure 
12,  Page  73.  The  left  of  the  cut  shows  the  unsprayed  portion  of  the 
field  and  the  right  the  sprayed  portion. 

See  caution  regarding  the  handling  of  Paris  green,  given  on 
page  37. 

WHY  GROWERS  DO  NOT  SPRAY 

Beet  growers  have  innumerable  excuses  for  not  spraying,  few  of 
which  will  stand  the  test. 

73 


Fig.  12.     Result  of  Spraying — Left,  Unsprayed; 
Right,   Sprayed 


Sugar  Beet  Webworm 

Cost  Too  High 

The  cost  is  one  of  the  reasons  most  frequently  given  for  not  spraying. 
It  costs  not  to  exceed  $3.00  an  acre  to  apply  Paris  green  with  labor  at 
$3.00  per  day  and  Paris  green  at  50  cents  per  pound.  One  thorough 
spraying  may  save  the  grower  $20.00  worth  of  beets.  Even  though  a 
moderate  amount  of  damage  is  done  in  spite  of  the  spraying,  a  saving  of 
one  ton  or  $10.00  an  acre  can  be  made. 

Spraying  Interferes  with  Haying 

Some  growers  will  not  spray  because  it  is  haying  time  when  the 
worms  appear.  Two  men  and  one  team  can  handle  at  least  1 5  acres  a 
day  and  should  do  20  to  25  acres.  If  a  grower  has  25  acres  he  can  spray 
it  in  one  day  and  save  one  or  two  tons  of  beets  per  acre  or  $250.00  to 
$500.00  in  a  day  by  spending  a  day's  time  and  $75.00  for  labor  and  poison. 
This  is  not  a  bad  interest  on  his  investment. 

Fear  of  Poisoning  Stock 

The  fear  of  poisoning  stock  by  feeding  sprayed  beet  tops  often  keeps 
a  grower  from  spraying.  As  sprayed  beet  tops  have  been  fed  for  many 
years  without  killing  stock,  this  excuse  seems  to  have  no  foundation. 
The  fact  that  only  a  portion  of  the  leaves  present  when  the  spraying  is 
done  ever  enter  the  feed  lot,  because  they  have  died  and  fallen  off,  to- 
gether with  the  fact  that  the  poison  is  very  easily  washed  off  by  showers, 
would  seem  to  reduce  the  question  of  poisoning  stock  to  the  very  remotest 
of  possibilities — so  remote  in  fact  that  it  need  not  be  considered  at  all. 

Fear  of  Breaking  Beet  Leaves 

The  fear  of  breaking  off  some  of  the  beet  leaves  with  the  spray 
machines  and  team  often  keeps  growers  from  spraying.  The  presence 
of  a  very  few  worms  in  a  field  will  reduce  the  leaf  surface  of  a  crop  much 
more  than  all  the  leaves  that  will  be  broken  off  during  the  spraying. 
The  fact  that  there  is  only  a  hole  here  and  there  in  the  leaves  makes  the 
damage  appear  slight,  but  it  does  not  take  many  such  holes  to  equal  the 
area  of  a  whole  leaf,  although  the  loss  is  not  nearly  so  apparent  as  when 
the  whole  leaf  is  broken  off. 

Hard  to  Realize  Danger 

It  is  often  very  hard  for  growers  to  realize  that  there  is  going  to  be 
any  damage.  The  worms  are  small  and  inconspicuous,  which  makes 
their  numbers  appear  insignificant  as  compared  with  the  foliage  of  the 
beets.  If  in  doubt  yourself  and  the  Sugar  Company  representative 
advises  spraying,  remember  that  this  man  has  no  interest  in  your  spend- 
ing more  money  on  your  crop  unless  by  so  doing  you  can  produce  a 
better  crop. 

DESCRIPTION 
The  Egg 

The  eggs  of  the  sugar  beet  webwormmoth  (Fig.  5,  Plate  V,  Page  19)  are 
about  the  size  of  a  small  pin-head,  of  a  pearly  white  color  when  first  laid, 
becoming  yellowish  as  the  young  worm  develops  within.  When  depos- 
ited singly  they  appear  as  shown  at  "A"  of  the  figure.  They  often 

74 


Sugar  Beet  Webworm 

occur  in  groups  of  from  two  to  five  or  six  or  even  more,  when  they  are 
placed  in  rows,  the  eggs  overlapping  as  shown  at  "B"  and  "C." 

The  Worm 

Figure  3,  "A,"  Plate  V,  Page  19  shows  a  young  webworm,  natural 
size,  on  a  beet  leaf.  Figure  4,  Plate  V,  Page  19  shows  this  same  worm 
much  enlarged.  As  they  grow  larger  these  worms  become  darker, 
appearing  more  like  the  full  grown  worms. 

The  full  grown  worm  is  shown  enlarged  in  Figure  6,  Plate  V,  Page 
19.  They  are  not  very  variable  in  color,  although  some  individuals 
are  somewhat  lighter  than  the  figure.  The  most  characteristic  marking 
is  the  dark  line  in  the  center  of  the  back  with  the  row  of  dark  circles  on 
either  side,  each  with  a  small  bristle  in  the  center.  These  circles  are 
grouped  in  pairs.  When  disturbed  the  worms  jerk  their  bodies  violently 
from  side  to  side,  often  throwing  themselves  from  the  leaf. 

The  Pupa  and  Cocoon 

The  cocoon  (Fig.  8,  Plate  V,  Page  19)  is  composed  of  silk  which  is 
produced  by  the  worm.  These  silken  tubes,  which  are  often  1|  to  2 
inches  long,  reach  to  the  surface  of  the  soil.  When  removed  with  the 
earth  adhering  to  them  they  appear  like  small  earthen  rods.  The  light 
portion  of  the  figure  shows  where  the  soil  has  been  scraped  away,  re- 
vealing the  cocoon  beneath. 

The  pupa  (Fig.  9,  Plate  V,  Page  19)  is  very  active.  When  disturbed 
it  will  twist  and  squirm  about  in  very  much  the  same  manner  as  the  worm. 
At  the  tip  are  eight  curved  spines,  four  on  either  side,  as  shown  in  Figure 
10,  Plate  V,  Page  19. 

The  Moth 

The  moth  (shown  natural  size,  Fig.  11,  Plate  V,  Page  19),  with 
its  delicate  shades  of  gray,  brown  and  tan,  harmonizes  so  well  with  the 
colors  of  the  soil  that  when  resting  on  the  ground  it  is  hard  to  distinguish 
from  its  surroundings.  When  at  rest  its  wings  are  folded  over  the  body 
so  that  the  moth  is  triangular  in  form  like  the  outline  drawing  to  the  left 
of  Figure  4,  Plate  VI,  Page  21 .  When  disturbed  the  moths  fly  up,  mak- 
ing short,  jerky,  zigzagging  flights. 

LIFE  HISTORY 

The  first  webworm  moths  appear  during  the  latter  part  of  April  and 
early  May.  About  the  first  of  June  the  moths  of  this  first  brood  of  the 
season  are  most  numerous. 

After  mating  takes  place  each  female  deposits  several  hundred  eggs 
on  sugar  beets  or  on  lamb's-quarters,  Russian  thistle,  alfalfa  and  other 
plants  growing  in  the  field  and  along  the  ditch  banks  and  fence  rows. 

At  the  end  of  from  three  to  five  days  hundreds  of  hungry  little  worms 
hatch  and  begin  their  work  of  destruction. 

Feeding  continues  from  two  to  three  weeks,  the  amount  eaten 
daily  increasing  very  rapidly  until  the  worms  are  full  grown.  During 
the  last  two  or  three  days  before  they  enter  the  soil  to  pupate,  the  amount 
eaten  is  appalling. 

75 


Sugar  Beet  Webworm 

When  full  grown  the  worms  burrow  into  the  soil  and  by  much 
wriggling  and  twisting  about  form  a  long  cell  extending  from  the  surface 
to  a  depth  of  1*  to  2  inches.  When  the  cell  is  completed  the  worm  pro- 
ceeds to  line  it  with  silk,  which  it  spins  into  a  tough,  leathery  cocoon- 

After  the  cocoon  is  completed  the  worm  begins  to  shorten  and  De- 
comes  very  much  wrinkled.  All  this  time  the  pupal  case  has  been  form- 
ing just  under  the  worm's  skin,  which  breaks  and  the  pupa  wriggles  its 
way  out. 


Fig.  13.     A  Portion  of  the  Compound  Eye  of  a  Tiger-beetle,  highly 
magnified.     (See  page  131) 

While  in  the  pupal  stage  legs,  wings,  antennae  and  a  long  proboscis 
with  which  the  moth  will  suck  the  nectar  from  the  alfalfa  and  other 
flowers  upon  which  it  feeds,  two  compound  eyes,  each  composed  of  many 
smaller  ones  (See  Fig.  13),  and  a  covering  of  feather-like  scales,  are 
formed.  After  all  this  is  completed  the  moth  comes  forth. 

These  moths  from  the  first  brood  of  worms  mate  and  the  females  lay 
the  eggs  for  the  next  brood.  These  worms  pass  through  the  same  changes 
as  the  first  until  they  enter  the  soil.  All  make  cells  like  those  of  the  first 
brood  worms  and  line  them  with  silk.  Only  a  small  portion  of  them 
pupate  in  the  fall,  however.  The  greater  number  remain  unchanged  in 
their  cells  until  the  following  spring.  With  the  coming  of  warm  weather 
they  change  to  the  pupa  and  after  ten  days  or  two  weeks,  to  moths,  which 
are  the  first  moths  to  appear  in  the  spring. 

76 


Sugar  Beet  Webworm 

The  worms  which  pupate  in  the  fall  become  moths  in  about  ten  or 
twelve  days.  After  breaking  out  of  the  silken  cocoons  these  moths  mate 
and  the  females  lay  eggs  for  a  third  brood.  When  full  grown,  the  worms 
of  this  brood  enter  the  ground,  where  they  remain  in  their  cocoons,  as 
worms,  until  spring. 

How  wisely  Nature  has  provided  for  the  carrying  of  the  beet  web- 
worm  over  the  winter!  For  fear  that  an  early  winter  overtake  the  last 
brood  in  the  fall  and  they  perish,  a  part  of  the  second  brood  is  set  aside 
as  a  sort  of  sinking  fund  against  such  a  calamity.  There  is  a  considerable 
overlapping  of  the  broods,  so  that  the  eggs  and  several  sizes  of  worms  may 
be  present  at  one  time. 

NATURAL  ENEMIES 
Ichneumon -flies 

The  dusky  winged  parasite  9  (Fig.  7,  Plate  V,  Page  19)  is  one  of  the 
most  common  enemies  of  the  sugar  beet  webworm.  The  larva  of  this 
parasite  develops  within  the  webworm,  but  does  not  kill  it  until  after  it 
has  entered  the  ground  and  spun  its  cocoon.  Then  instead  of  the  moth, 
the  parasite  emerges  from  the  cocoon. 

This  parasite  has  four  dusky  wings.     Near  the  center  of  each  of  the 
forward  pair  is  a  partially  clear  area.     The  body  is  dark  reddish  or  bay 
and  the  legs  have  dark  bands  which  give  them  the  appearance  of  being 
ringed. 
Braconids 

The  little  wasp-like  parasite  3  (Fig.  14,  Plate  V,  Page  19),  which  is  a 
Braconid,  frequently  emerges  from  a  cocoon  instead  of  the  webworm 
moth. 

Tachina-flies 

The  Tachina-fly  16  (Fig.  13,  Plate  V,  Page  19)  fastens  its  eggs  onto 
the  webworm  and  when  the  maggots  hatch  they  burrow  into  it.  At  first 
the  webworm  appears  to  be  little  disturbed  by  the  maggots,  but  as  the 
latter  increase  in  size  their  feeding  weakens  the  worm,  which  finally  dies. 
When  fully  grown,  the  maggots  change  to  pupae  inside  the  puparium 
(Fig.  12,  Plate  V,  Page  19).  The  adult  fly  breaks  open  the  end  of  the 
puparium,  as  shown  in  the  figure,  and  escapes. 

Solitary  Wasp 

One  of  the  enemies  of  the  sugar  beet  webworm  belongs  to  a  group  of 
wasps  known  as  solitary  wasps.  (See  page  135.) 

This  wasp13  (Fig.  15,  Plate  VI,  Page  21)  places  its  eggs  in 
tunnels,  one  of  which  is  shown  in  cross  section  in  Figure  14,  Page  78. 
These  tunnels  are  dug  in  the  soil  about  the  borders  of  fields. 

The  mouth  of  the  tunnel  is  always  built  up  a  half  inch  or  so  above  the 
surface  of  the  soil.  When  the  nest  is  completed  several  web  worms  are 
caught  and  after  being  stung,  which  paralyzes  them,  they  are  placed  at 
the  bottom  of  the  tunnel.  After  a  single  egg  is  deposited  among  the 
worms  a  wall  is  built  so  as  to  make  a  small  cell  at  the  lower  end  of  the 
tunnel.  The  chimney-like  mouth  is  next  filled  with  mud.  The  larva 
which  hatches  from  the  egg  feeds  upon  the  webworms  until  ready  to 
change  to  the  pupa.  This  change  takes  place  in  the  burrow,  from  which 
the  adult  wasp  escapes  by  digging  its  way  out. 

(j-»_u-i»^  See  explanation  »f  "Reference  Figures."  page  2 

77 


Sugar  Beet  Webworm  True  Army  Worm 


Fig.   14.     Cross    Section  through   Burrow   of  the   Solitary   Wasp 
Robber-flies 

There  is  a  family  of  flies  commonly  known  as  robber-flies  (Fig.  12, 
Plate  VI,  Page  21),  the  members  of  which  prey  upon  other  flies,  as  well 
as  upon  bees  and  their  near  relatives,  small  flying  beetles  and  moths. 
These  flies  will  often  be  noticed  resting  on  the  ground  or  some  object 
which  furnishes  a  clear  view  of  the  surroundings,  patiently  waiting  for 
some  victim  to  appear.  Their  heads  are  joined  to  the  body  by  a  freely 
moving  neck  so  that  they  can  be  moved  at  will.  While  waiting  for  some 
ill-fated  fly  to  appear  the  head  is  moved  about  following  the  flight  of 
passing  insects  in  really  human  fashion. 

These  flies  capture  their  victims  by  pouncing  upon  them  in  true  bird 
of  prey  fashion.  Holding  the  victim  with  their  long  legs,  the  beak  is 
thrust  into  its  body  and  the  contents  sucked  up.  One  of  these  flies  was 
observed  to  capture  and  feed  upon  a  webworm  moth. 

(b)     TRUE  ARMY  WORM 

(Figs.  21,  22,  24  and  25,  Plate  I,  Page  11) 

The  true  army  worm  is  one  of  those  insects  which,  while  always 
present  in  small  numbers  in  our  fields,  commonly  escapes,  unobserved, 
because  of  its  seclusive  habits.  However,  when  for  any  reason  the  natural 
checks  become  abnormally  scarce  or  favorable  weather  conditions  prevail 
in  connection  with  a  plentiful  food  supply,  it  multiplies  very  rapidly, 
overrunning  our  fields  in  vast  hordes,  often  traveling  in  such  large  num- 
bers that  the  very  earth  seems  to  move.  All  follow  the  same  general 
direction,  destroying  crops  as  they  go,  and  leaving  nothing  but  the 
riddled  remains  of  what  a  few  days  before  gave  promise  of  a  bountiful 
harvest. 

78 


True  Army  Worm 
NATURE  OF  INJURY 

In  the  case  of  leaf-eating  insects  the  damage  done  is  usuaHy  pro- 
portionate to  the  amount  of  leaf  surface  destroyed.  However,  the  true 
army  worm  is  an  exception  to  this  rule.  When  feeding,  these  worms 
have  the  habit  of  climbing  grass  and  grain  stalks  and  gnawing  off  the  heads. 
When  grain  is  in  the  shock,  especially  if  harvested  a  little  green,  the  heads 
are  often  gnawed  off  also.  For  this  reason  the  damage  greatly  exceeds 
that  of  most  insects  of  this  class  in  that  the  army  worm  destroys  much 
more  than  it  actually  eats. 

Sugar  beets  are  seldom  damaged  except  where  they  lie  in  the  path  of 
the  moving  worms  or  next  to  infested  small  grain  or  grass  crops.  When 
attacking  this  crop  the  worms  overrun  the  leaves,  at  the  same  time  eating 
irregular  areas  out  of  their  margins.  In  case  of  severe  injury  all  of  the 
leaves  with  the  exception  of  the  coarse  stems  may  be  destroyed.  The 
roots  are  seldom,  if  ever,  eaten.  The  army  worm  usually  appears  so  late 
in  the  season  that  few  beets  are  killed. 

METHODS  OF  CONTROL 
Spraying 

When  the  nature  of  the  crop  attacked  is  such  that  poison  can  be 
applied  in  the  form  of  a  spray,  without  danger  of  poisoning  either  live 
stock  or  human  beings  that  use  the  crop  as  a  food,  the  army  worm  can  be 
effectively  controlled  by  spraying  with  Paris  green  or  lead  arsenate. 
The  same  proportions  of  poison  and  water  should  be  used  as  in  the  control 
of  the  beet  webworm ;  i.  e.,  4  pounds  of  Paris  green  or  16  pounds  of  arsenate 
of  lead  paste  to  the  amount  of  water  used  in  spraying  an  acre.  Remem- 
ber that  the  sprayer  should  be  adjusted  so  as  not  to  apply  more  than  100 
to  125  gallons  per  acre. 

Poisoned  Bait 

When  the  food  supply  has  become  exhausted  and  the  worms  have 
started  across  country  in  search  of  new  pasturage,  the  poisoned  bait 
recommended  in  the  control  of  cutworms  will  prove  most  effective.  (See 
pages  39  and  40.)  This  should  be  scattered  in  the  path  of  the  worms. 
Several  strips  of  a  rod  or  so  wide  with  about  the  same  distance  between 
them  will  give  the  best  results.  As  the  worms  are  most  active  during 
the  latter  part  of  the  afternoon  this  is  the  best  time  to  put  out  the  bait ; 
however,  if  the  army  is  on  the  move  earlier,  the  poison  should  be  scattered 
earlier. 

Furrow  Trap 

This  consists  of  a  furrow  plowed  across  the  path  of  the  advancing 
worms.  The  soil  should  be  thrown  toward  the  worms  so  as  to  leave  the 
perpendicular  side  of  the  furrow  opposite  them.  Post  holes  should  be 
bored  in  the  bottom  of  the  furrow  every  few  feet.  As  the  worms  enter 
the  furrow  they  will  attempt  to  climb  up  the  perpendicular  side.  Many 
failing  in  this  will  wander  up  and  down  the  furrow  in  search  of  a  place 
where  they  can  climb  out.  In  this  way  many  will  fall  into  the  post  holes. 
The  worms  thus  trapped  can  be  killed  by  crushing  them  with  a  piece  of 
wood  or  by  pouring  a  small  quantity  of  kerosene  into  each  hole.  Some- 
times the  post  holes  are  not  used.  In  their  stead  a  small  log  or  heavy 

79 


True  Army  Worm 

post  is  hauled  up  and  down  the  furrow  to  crush  the  worms.     The  furrow 
in  connection  with  the  poisoned  bait  makes  a  very  effective  combination. 

DESCRIPTION 
The  Egg 

The  eggs  have  a  smooth  shining  surface.  When  first  laid  they  are 
of  a  pearly  white.  As  the  young  worm  develops  the  color  changes  to  a 
creamy  flesh  color,  gradually  becoming  darker  until  just  before  the  young 
worm  emerges,  when  it  is  a  dull  gray. 

The  moths  appear  to  prefer  the  dense  growth  of  grass  or  grain  which 
commonly  grows  on  old  stack  bottoms  or  about  manure  piles  or  the 
droppings  of  animals  in  pastures,  as  places  to  deposit  their  eggs.  Injury 
to  small  grain  is  often  first  observed  where  this  heavy  growth  occurs 
on  old  stacking  grounds. 

The  eggs  often  occur  in  clusters  of  a  hundred  or  more.  Usually 
they  are  deposited  in  the  sheath  of  grass  and  grain  leaves,  sometimes 
between  two  leaves  which  happen  to  be  fastened  together.  Egg  laying 
takes  place  during  the  night.  A  single  female  moth  has  been  known  to 
lay  254  eggs,  and  as  many  as  800  developed  and  undeveloped  eggs  have 
been  taken  from  the  abdomen  of  one  moth.* 

The  Worm 

In  from  eight  to  ten  days  after  the  eggs  are  laid,  the  young  worms 
appear.  As  they  emerge  from  the  egg  they  are  whitish  with  brown  heads. 
The  first  act  of  the  newly  hatched  worm  is  to  eat  the  shell  of  the  egg  from 
which  it  has  just  escaped. 

During  the  course  of  their  development  the  worms  shed  their  skins 
several  times.  As  soon  as  the  worm  has  cast  off  its  old  coat  it  proceeds 
to  devour  it  as  if  attempting  to  cover  up  its  trail. 

The  full  grown  worms  (Figs.  21  and  22,  Plate  I,  Page  1 1)  are  variable 
in  color,  some  being  considerably  lighter  than  the  figures.  The  figures 
are  so  lifelike  that  a  description  of  the  coloring  is  not  necessary.  When 
disturbed  the  worms  curl  up  as  shown  in  Figure  21.  This  is  not  char- 
acteristic of  the  army  worms  alone,  however,  as  many  caterpillars,  espec- 
ially cutworms,  have  the  same  habit.  When  fully  grown  the  army  worms 
enter  the  soil,  where  they  form  a  cell  in  the  same  way  as  the  cutworms. 
In  this  cell  the  worm  spins  a  thin,  silken  cocoon  within  which  it  changes 
to  the  pupa. 

The  Pupa 

The  pupa  (Fig.  24,  Plate  I,  Page  11)  of  the  army  worm  does  not 
differ  greatly  from  that  of  the  cutworms  already  mentioned.  At  first  it 
is  a  light  creamy  yellow.  When  fully  colored  it  is  of  a  rich  mahogany 
brown.  At  the  tip  there  are  four  spine-like  appendages  as  shown  in  the 
figure.  After  spending  from  two  to  three  weeks  in  the  pupal  stage  the 
moths  appear. 

The  Moth 

The  moth  (Fig.  25,  Plate  I,  Page  11)  is  a  night  flyer  and  is  seldom 
seen  on  the  wing  during  the  day  unless  the  weather  is  cloudy  and  damp. 

*Davis  and  Satterthwait,  "Life  History'  Studies  •f  Cirphis  unifiuncta,  the  True  Army  W«rm."  Journal 
•f  Agricultural  Research.  V«l.  VI.  No.  21  (1914). 

80 


True  Army  Worm  Alfalfa  Looper 

The  most  characteristic  marking  is  the  white  spot  near  the  center  of  each 
fore  wing.  The  last  part  of  the  army  worm's  Latin  name,  " unipuncta," 
is  derived  from  this  spot  and  means  one  point. 

LIFE  HISTORY 

So  far  as  known,  the  army  worm  passes  the  winter,  in  the  north- 
ern half  of  the  United  States,  as  a  partially  grown  worm  or  larva. 
The  first  moths  appear  during  May  or  June,  depending  upon  the  season 
and  the  locality.  The  cooler  the  season  and  the  farther  north  we  go  the 
later  they  appear. 

The  eggs  are  laid  soon  after  the  moths  emerge,  and  the  young  worms 
appear  during  June.  These  feed  for  about  three  weeks  and  then  change 
to  pupae,  in  which  form  they  remain  from  eight  to  eleven  or  twelve  days, 
when  the  adult  moths  come  forth. 

The  second  brood  is  in  the  egg  stage  about  the  middle  of  July,  in  the 
worm  stage  during  the  latter  part  of  July  and  early  August,  in  the  pupal 
stage  during  the  latter  part  of  August,  and  the  moths  issue  between  the 
the  last  of  August  and  the  8th  or  10th  of  September. 

The  third  brood  of  worms  hatches  during  the  latter  part  of  Septem- 
ber and  early  October.  These  worms  spend  the  winter  as  partially 
grown  larvae  and  complete  their  development  the  next  April. 

In  the  southern  part  of  the  country  a  fourth  generation  may  occur. 

NATURAL  ENEMIES 
Parasitic  Flies 

Several  species  of  parasitic  flies  destroy  the  army  worm.  Two 
species,  "Archytus  apicifere  Walk"  and  a  "Winthemia"*  -species  (near 
militaris  Walsh)  have  been  bred  from  parasitized  army  worms  taken 
in  Boulder  County,  Colorado. 

Birds 

Birds,  especially  blackbirds,  meadow  larks  and  other  ground  feeding 
species,  render  valuable  service  in  destroying  these  worms. 

Ground  Beetles 

Ground  beetles  and  their  larvae  also  devour  large  numbers  of  army 
worms. 

(c)     ALFALFA  LOOPER 
(Figs.  5,  6,  7  and  8,  Plate  VI,  Page  21) 

The  first  authentic  record  of  this  insect  as  a  crop  pest**  states  that 
during  June,  1895,  considerable  damage  was  done  to  alfalfa  near  Grand 
Junction,  Colorado,  by  the  caterpillars.  Again  in  1914  reports  of  injury 
by  this  insect  came  from  the  same  locality.  The  same  year  the  looper 
also  appeared  in  large  numbers  in  the  Yellowstone  Valley  in  Montana 
and  in  adjoining  territories,  where  considerable  damage  was  done  to  both 
alfalfa  and  sugar  beets.  The  latter  were  damaged  only  in  those  instances 
where  the  worms  migrated  from  alfalfa  fields  or  the  sweet  clover  growing 
on  waste  land. 


•Determined  by  C.  H.  T  Townsend. 

**J.  A.  Hyslop.""The  Alfalfa  Looper."  Bulletin  No.  95.  Part  VII.  Bureau  of  Entomology.  U.  S. 
Department  of  Agriculture  (1912). 

81 


Alfalfa  Looper 

NATURE  OF  INJURY 

The  injury  to  sugar  beets  is  similar  to  that  caused  by  other  leaf- 
eating  caterpillars.  The  destruction  of  the  leaves  reduces  the  yield  and 
sugar  content  of  the  crop. 

Both  the  leaves  and  blossoms  of  alfalfa  are  eaten.  1  his  reduces  the 
yield  and  quality  of  hay.  The  destruction  of  the  blossoms  reduces  the 
yield  of  seed  where  the  crop  is  grown  for  seed  production. 

METHODS  OF  CONTROL 

As  this  insect  seldom  if  ever  attacks  sugar  beets  until  its  favorite 
food  plants  (alfalfa  and  sweet  clover)  are  exhausted,  such  attacks  can  be 
anticipated  and  preventive  measures  employed  to  protect  the  crop. 

Furrow  Trap 

In  case  sugar  beets  adjoin  infested  alfalfa  or  waste  land  overgrown 
with  sweet  clover  the  furrow  trap  recommended  for  the  control  of  the  true 
army  worm  (page  79)  can  be  used  with  good  results.  The  furrow  should 
be  thrown  away  from  the  beets  so  as  to  leave  the  perpendicular  side  next 
to  them.  If  water  is  available  a  small  stream  in  the  furrow  will  add  to 
its  effectiveness. 

Poisons 

Where  the  loopers  are  feeding  on  alfalfa  or  sweet  clover  growing  on 
ditch  banks  or  fence  rows  about  beet  fields  these  plants  should  be  sprayed 
with  Paris  green  or  arsenate  of  lead,  using  2  to  3  pounds  of  the  former  or 
8  to  1 2  pounds  of  the  latter  if  the  paste  is  used,  or  4  to  6  pounds  of  the  dry 
form,  to  50  gallons  of  water. 

If  the  caterpillars  have  entered  a  beet  field,  spray  the  beets,  using 
the  proportions  of  poison  and  water  given  above. 

Bunches  of  freshly  cut  green  alfalfa  or  sweet  clover,  sprayed  with 
Paris  green  and  placed  in  the  furrow,  where  the  furrow  trap  is  used,  will 
kill  many  of  the  loopers. 

Mowing 

Where  alfalfa  is  being  damaged  it  should  be  mowed  at  once.  The 
longer  it  stands  the  poorer  the  quality  will  be.  After  the  hay  is  removed 
the  stubble  should  be  sprayed  to  destroy  the  worms  and  protect  the  new 
growth. 

If  strips  of  alfalfa  are  left  uncut  at  intervals  through  the  field  the 
loopers  will  congregate  on  these  and  can  then  be  killed  by  spraying  the 
standing  alfalfa.  When  the  worms  have  been  destroyed  the  alfalfa  on 
the  strips  can  be  removed.  This  hay  should  not  be  fed  unless  heavy 
rains  have  washed  off  the  poison. 

Close  watch  should  be  kept  of  the  worms  after  the  infested  hay  is 
cut  to  prevent  their  migrating  to  adjoining  crops. 

DESCRIPTION 
The  Egg 

The  eggs  are  pale  yellow,  hemispherical  in  shape,  rounded  at  the  base, 
the. apex  with  a  rounded  depression,  and  are  finely  creased  vertically.* 

*J.  A  Hyslop  "The  Alfalfa  Looper."  Bulletin  No.  95.  Part  VII.  Bureau  of  Entomology.  U.  S. 
Department  of  Agriculture  (1912). 

82 


Alfalfa  Looper 

The  eggs  are  deposited  on  the  food  plants.  Moths  have  been  ob- 
served in  the  act  of  laying  at  three  o'clock  in  the  afternoon.* 

The  Caterpillar 

These  caterpillars  differ  from  all  others  discussed  in  this  Bulletin 
in  having  but  three  prolegs  on  each  side  of  the  posterior  half  of  the  body. 
By  comparing  Figure  1  and  Figure  5,  Plate  VI,  Page  21,  this  difference  is 
made  more  apparent.  It  will  be  noticed  that  Figure  1  has  four  legs  just 
back  of  the  center,  and  one  at  the  tip  of  the  body,  and  that  Figure  5,  which 
represents  a  full  grown  alfalfa  looper,  has  but  three  including  the  one  at 
the  tip. 

The  alfalfa  loopers  vary  greatly  in  color. 

The  darker  parts  of  different  individuals  range  from  a  dark  olive 
brown  to  pale  greenish  brown.  The  figure  represents  one  of  the  lighter 
type. 

The  Cocoon 

The  cocoon  (Fig.  6,  Plate  VI,  Page  21)  is  made  of  several  leaves  of 
the  host  plant  held  together  by  loosely  woven  silk  threads.  Sometimes 
the  cocoons  are  constructed  among  dead  leaves  and  trash  on  the  ground. 

The  Pupa 

After  the  worm  has  completed  its  cocoon  it  changes  to  the  pupa 
within  it.  The  pupa  (Fig.  7,  Plate  VI,  Page  21)  is  very  similar  to  those 
of  the  cutworms  and  army  worms. 

The  Moth 

The  adult  (Fig.  8,  Plate  VI,  Page  21)  is  one  of  our  most  beautiful 
moths.  The  figure  is  so  true  to  life  that  no  description  is  necessary. 
The  silvery  spot  near  the  center  of  the  fore  wing  is  characteristic  of  this 
and  related  moths. 

LIFE  HISTORY 

This  insect  probably  passes  the  winter  in  hibernation  in  the  pupal 
stage.  During  the  latter  part  of  May  and  early  June  the  eggs  for  the  first 
brood  of  worms  of  the  season  are  laid. 

The  length  of  the  egg  stage  is  not  definitely  known.  The  worms 
feed  for  about  two  weeks,  at  the  end  of  which  time  the  cocoon  is  made 
and  the  change  to  the  pupal  stage  takes  place.  This  lasts  about  ten  to 
twenty  days  during  ordinary  summer  weather. 

The  first  adults  of  the  second  brood  appear  during  late  June  and  early 
July.  There  are  two  and  possibly  three  generations  each  season. 

NATURAL  ENEMIES 

The  alfalfa  looper  appears  to  be  a  favorite  host  of  many  parasites. 
The  Ichneumon-fly  8,  shown  in  Figures  9  and  10,  Plate  VI,  Page  21,  was 
reared  from  alfalfa  loopers  taken  at  Edgar,  Montana,  and  several  other 
species  have  been  reared  from  alfalfa  loopers  by  Mr.  Hyslop. 

Many  of  the  caterpillars  succumb  to  a  bacterial  disease.  The  in- 
fected worms  become  dark  in  color  soon  after  dying.  The  dead  worms 

*Mr.  Koebels.  Bureau  of  Entomology  Notes.  No.  95-K. 
(")  See  explanation  of  "Reference  Figures."  page  2. 

83  ! 


Alfalfa  Looper  Alfalfa  Webworm 

hang  limp  from  the  host  plant  at  first,  but  finally  the  body  becomes  so 
decayed  that  it  drops  to  the  ground. 

(d)     ALFALFA  WEBWORM* 

(Figs.  1.  2,  3  and  4,  Plate  VI,  Page  21) 

During  the  summer  of  1914  the  alfalfa  web  worm  l  appeared  in 
large  numbers  in  Northern  Colorado,  where  it  did  considerable  damage 
to  first  cutting  alfalfa.  While  they  appear  to  prefer  this  crop  and  sweet 
clover,  the  worms  caused  some  anxiety  among  sugar  beet  growers  by 
feeding  upon  the  leaves  of  sugar  beets. 
NATURE  OF  INJURY 

When  attacking  alfalfa  the  worms  spin  masses  of  whitish  web  at  the 
tips  of  the  plants,  inclosing  the  new,  tender  leaves  and  blossoms.  This 
web  furnishes  protection  for  the  worms  while  they  feed  upon  the  inclosed 

Injury  to  sugar  beets  is  similar  to  that  caused  by  the  sugar  beet  web- 
worm.  Some  of  the  leaves  will  be  found  partially  covered  by  a  web  which 
terminates  in  a  long  tube  extending  to  the  ground,  the  lower  end  being 
among  the  clods  on  the  surface.  When  but  few  worms  are  present  there 
is  usually  only  one  to  a  plant. 

METHODS  OF  CONTROL 
Poison 

This  worm  can  be  controlled  on  sugar  beets  by  spraying  with  any 
arsenical  poison.  The  same  amounts  of  poison  should  be  used  as  for  the 
control  of  the  sugar  beet  web  worm  (pages  72  and  73),  and  should  be 
applied  in  the  same  way. 

Mowing 

In  case  alfalfa  is  being  damaged  it  should  be  cut  at  once,  cured  and 
put  up  to  prevent  loss.  After  removing  the  crop  the  stubble  can  be 
sprayed.  (See  "Mowing,"  page  82.) 

Irrigation 

Irrigating  after  the  worms  have  entered  the  ground  to  pupate  will 
seal  them  in,  preventing  many  moths  from  emerging  when  mature. 

DESCRIPTION 
The  Worm 

Although  closely  related  to  the  sugar  beet  webworm,  this  worm 
(Fig.  1,  Plate  VI,  Page  21)  is  easily  distinguished  from  it  by  its  coloring. 
The  central  portion  of  the  back  is  occupied  by  a  light  stripe  tinged  with 
flesh  color.  On  either  side  of  this  there  is  a  dark  stripe  about  the  same 
width.  Along  the  upper  and  lower  margins  of  these  dark  stripes  there 
are  several  dark  circular  spots,  each  bearing  a  hair-like  bristle.  With 
the  exception  of  those  segments  next  to  the  head  and  at  the  tip  of  the 
body,  each  segment  has  three  of  these  spots,  two  on  the  upper  border  of 

*This  is  a  local  name  applied  to  this  insect  in  Northern  Colorado.  This  insect  should  not  be  con- 
fused with  Loxostege  similaris  Guen."  which  is  also  called  the  alfalfa  webworm.  (See  Bulletin  109.  Okla- 
homa Agricultural  Experiment  Station.  February.  1916). 

0)  See  explanation  of  "Reference  Figures."  page  2. 

84 


Alfalfa  Webworm 

the  dark  stripe  and  one  on  the  lower.  Just  below  the  dark  stripe  is  an- 
other light,  more  or  less  flesh-colored  one,  and  below  this  the  body  is 
dusky,  but  not  so  dark  as  the  other  dark  portions.  There  are  several 
dark  circles  within  the  dusky  portion,  each  bearing  a  bristle.  The  lateral 
portions  of  the  first  segment  back  of  the  head  are  dark.  The  head  is 
mottled  with  dark  brown  on  a  lighter  ground  color. 

The  worms  are  very  active.  If  their  webbed  retreats  on  alfalfa  are  dis- 
turbed they  throw  themselves  to  the  ground  or  run  rapidly  down  the 
stems. 

When  on  sugar  beets  they  will  be  found  concealed  at  the  end  of  the 
long,  silken  tube  already  mentioned,  among  the  clods  near  the  crown  of 
the  plant.  If  the  soil  is  disturbed  the  worms  run  rapidly  to  the  web 
among  the  leaves,  and  if  disturbed  here  they  descend  to  the  end  of  the 
tube  again  just  as  rapidly.  They  appear  to  travel  backward  as  freely  as 
forward. 

The  Pupa 

When  fully  grown  the  worms  enter  the  soil  and  spin  a  cocoon  very 
similar  to  that  of  the  sugar  beet  webworm,  but  more  loosely  made,  in 
which  they  change  to  the  pupa  (Fig.  2,  Plate  VI,  Page  21).  The  pupa  is 
very  much  like  that  of  the  beet  webworm,  but  can  be  readily  distinguished 
from  it  by  the  eight  spatulate  (spoon-shaped)  appendages  at  the  tip  (Fig. 

3,  Plate  VI,  Page  21),  those  of  the  sugar  beet  webworm  being  curved  and 
pointed. 

The  Moth 

In  warm  weather  the  moths  appear  in  about  six  or  eight  days  after 
the  worms  change  to  pupae.  By  comparing  the  figure  of  this  moth  (Fig. 

4,  Plate  VI,  Page  21)  with  that  of  the  sugar  beet  webworm  (Fig.  11, 
Plate  V,  Page  19),  the  differences  are  clearly  brought  out.     It  will  be 
noticed  that  the  under  wings  of  the  alfalfa  webworm  are  much  darker 
than  those  of  the  sugar  beet  webworm  moth  and  that  the  markings  of  the 
upper  or  fore  wings  are  darker  as  well  as  different  in  form.     Flying  in  the 
field  the  two  are  very  hard  to  distinguish  from  each  other. 

LIFE  HISTORY 

So  far  as  known  to  the  writer,  there  are  no  published  accounts  of  the 
life  history  of  this  insect.  In  general  it  is  probably  quite  similar  to  that 
of  the  sugar  beet  webworm.  The  injury  to  alfalfa  referred  to  above 
occurred  during  the  last  of  June.  The  moths  of  this  brood  appeared  July 
14th.  During  August  another  brood  of  worms  appeared.  This  second 
brood  was  not  so  numerous  and  did  less  damage  than  the  first.  In  all 
probability,  in  the  latitude  of  Denver,  the  winter  is  passed  in  the  larval 
or  pupal  stage. 

NATURAL  ENEMIES 

An  undescribed  Tachina-fly,  15  (Fig.  11,  Plate  VI,  Page  21),  was 
reared  from  caged  worms. 

Birds  and  poultry  no  doubt  do  much  to  hold  this  insect  in  check. 

(»'»)  See  explanation  of  "Reference  Figures."  page  2. 

85 


Yellow-bear  Caterpillar 

(e)     YELLOW-BEAR  CATERPILLAR 

(Figs.  15  and  16,  Plate  V,  Page  19) 

The  yellow-bear  caterpillar  is  always  in  evidence,  in  small  numbers, 
on  Russian  thistle,  lamb's-quarters  and  other  weeds  along  the  fence 
rows,  ditch  banks  and  roadsides.  As  a  rule  they  are  not  numerous  enough 
to  cause  noticeable  damage  to  crops.  Occasionally,  however,  they  become 
so  numerous  that  the  wild  food  plants  are  not  sufficient  for  their  support. 
At  such  times  the  caterpillars  attack  whatever  growing  crop  happens  to 
be  nearest  at  hand.  Such  an  outbreak  occurred  during  August  and  Sep- 
tember, 1909,  in  the  Arkansas  Valley  in  Southern  Colorado.* 

NATURE  OF  INJURY 

When  young  the  worms  eat  only  the  surface  of  the  leaves  but  as  they 
become  older  and  larger  the  margins  of  the  leaves  are  eaten  away  and  holes 
are  eaten  into  them.  When  very  numerous,  crops  are  completely  defoli- 
ated by  these  caterpillars,  or  in  the  case  of  sugar  beets  the  stems,  midribs 
and  young  heart  leaves  only  are  left  untouched.  Severe  attacks  on  sugar 
beets  result  in  a  lowering  of  the  yield  and  sugar  content  of  the  crop. 

The  yellow-bear  is  one  of  the  most  general  feeders  among  the  whole 
list  of  crop  pests.  The  following  list  of  plants  injured  is  given  by  Mr. 
Marsh  in  the  bulletin  already  referred  to : 

Sugar  beet  Radish  Squash 

Stock  beet  Celery  Watermelon 

Table  beet  Carrot  Cantaloupe 

Rhubarb  Parsnip  Sweet  potato 

Cabbage  Egg  plant  Corn 

Cauliflower  Potato  Lima  bean 

Turnip  Pumpkin  String  bean 

Asparagus  Dahlia  Amaranthus 

Pea  Cherry  Chenopodium 

Peanut  Gooseberry  Helianthus 

Alfalfa  Blackberry  Solanum  rostratum 

Hollyhock  Raspberry  Verbesina 

Morning-glory  Currant  Ambrosia 

Canna  Grape  Russian  thistle 

Hyacinth  Dock  (Rumex)  Spanish  needle 

METHODS  OF  CONTROL 
Poison 

In  his  work  in  the  Arkansas  Valley  of  Colorado,  Mr.  Marsh  exper- 
imented with  both  Paris  green  and  arsenate  of  lead.  It  was  found  that 
arsenate  of  lead,  even  where  applied  in  quantities  as  high  as  8  pounds  to 
100  gallons  of  water,  was  of  little  value  in  the  control  of  the  yellow-bear 
caterpillar.  Paris  green  used  at  the  rate  of  10  pounds  to  100  gallons  of 
water  to  which  10  pounds  of  lime  was  added  to  prevent  injuring  the 
leaves  killed  practically  all  caterpillars  in  three  days. 

From  the  results  of  this  work  it  appears  that  this  worm  is  very  resist- 
ant to  arsenical  poisoning,  the  ordinary  amounts  being  practically  value- 
less in  its  control. 

*H-  O.  Marsh.  "Biologic  and  Economic  Notes  on  the  Yellow-bear  Caterpillar."  Bulletin  No.  82, 
Part  V.  Bureau  of  Entomology.  U.  S.  Department  of  Agriculture  (1910). 

86 


Yellow-bear  Caterpillar  Zebra  Caterpillar 

DESCRIPTION 
The  Egg 

The  eggs  are  laid  in  clusters  on  some  green  plant.  In  the  Arkansas 
Valley  Mr.  Marsh  found  large  numbers  of  eggs  on  rhubarb,  which  appears 
to  be  a  favorite  food  plant. 

The  Caterpillar 

Unlike  the  cutworms  and  the  other  caterpillars  so  far  considered  in 
this  Bulletin,  the  yellow-bear  is  completely  covered  with  a  coat  of  tawny 
hair.  This  varies  from  a  reddish  brown  in  the  darker  individuals  to  a  light 
yellow  or  straw  color  in  the  lighter  ones.  Figure  15,  Plate  V,  Page  19 
represents  one  of  the  lighter  type.  The  body  of  the  caterpillar  is  most 
often  pale  yellow  or  straw  color  with  a  darker  stripe  running  lengthwise 
on  either  side. 

The  Pupa 

The  pupa  is  more  robust  than  that  of  the  cutworms  already  men- 
tioned. Instead  of  entering  the  ground  to  pupate  the  worms  seek  some 
secluded  place  such  as  underneath  boards  and  other  objects  lying  on  the 
ground  or  among  the  dead  leaves  and  trash  about  the  borders  of  fields 
and  on  ditch  banks.  Here  the  caterpillar  forms  a  loose  cocoon  composed 
almost  entirely  of  its  own  hairs  held  together  by  threads  of  silk,  within 
which  it  changes  to  the  pupa  and  later  to  the  moth. 

The  Moth 

The  adult  yellow-bear  (Fig.  16,  Plate  V,  Page  19),  sometimes  known 
as  the  Virginian  tiger-moth,  is  one  of  our  most  delicate  night  fliers.  Pure 
white  with  dark  spots  on  the  wings  and  three  rows  of  black  dots  on  the 
body  alternating  with  two  yellow  stripes,  this  moth  presents  a  striking 
contrast  to  the  dusky  winged  cutworm  moths. 

LIFE  HISTORY 

This  moth  spends  the  winter  in  the  pupal  stage  concealed  under 
trash  along  fence  rows  and  ditch  banks  and  on  other  waste  ground.  The 
moths  appear  in  early  summer  to  deposit  the  eggs  for  the  first  brood  of 
worms,  which  become  mature  about  the  last  of  July.  The  second  brood 
appears  during  August  and  becomes  fully  grown  about  the  first  week  of 
September.  These  worms  pupate  after  spinning  the  loose  cocoon  already 
mentioned  and  remain  in  this  form  until  the  next  spring. 

NATURAL  ENEMIES 

The  natural  enemies  of  the  yellow-bear  appear  to  be  peculiarly  few. 
Because  of  their  covering  of  hair  few  birds  feed  upon  them.  Certain 
Tachina-flies  destroy  a  few  worms  and  in  some  localities  many  die  of  a 
fungous  disease.* 

(f)     ZEBRA  CATERPILLAR 
(Fig.  11,  Plate  III,  Page  15) 

This  is  one  of  our  most  striking  caterpillars.  When  resting  on  a 
beet  with  its  bright  colors  contrasted  with  the  dark  green  of  the  leaves 
it  is  almost  a  thing  of  beauty. 

*Botrytts  bcusiana  Bals. 

87 


Zebra  Caterpillar  Leaf-eating  Beetles 

NATURE  OF  INJURY 

The  zebra  caterpillar  bears  the  distinction  of  being  the  first  insect 
reported  as  damaging  beets  in  the  United  States.*  While  it  seems  to 
prefer  vegetable  crops,  especially  beets,  and  cabbage,  turnips,  and  other 
cruciferous  plants  in  general,  yet  it  feeds  upon  field  crops  and  even  the 
leaves  of  trees  and  shrubs. 

METHODS  OF  CONTROL 

Dr.  Chittenden*  states  that  this  insect  yields  readily  to  sprays  of 
arsenicals.  Paris  green  or  arsenate  of  lead,  the  former  at  the  rate  of  2  to 
3  pounds  and  the  latter  at  4  to  6  pounds  dry  or  8  to  12  pounds  of  the 
paste,  to  each  100  gallons  of  water,  will  give  satisfactory  results. 

DESCRIPTION 
The  Egg 

The  eggs  are  deposited  in  clusters  of  from  several  to  as  many  as  a 
hundred  or  more,  usually  on  the  under  side  of  the  leaves  of  the  food  plants. 

The  Caterpillar 

At  first  the  worms  are  whitish  in  color  with  dark  heads  and  several 
dark  spots  scattered  over  the  body.  While  small  they  feed  in  compact 
groups,  but  after  several  days  the  skin  is  shed  and  the  caterpillars  take  on 
the  colors  of  the  adult  worm  (Fig.  1 1,  Plate  III,  Page  15)  and  gradually 
become  scattered.  When  disturbed  the  worms  coil  up  and  fall  to  the 
ground. 

The  Moth 

The  moth  is  about  the  size  of  the  adult  western  army  cutworm  (Fig. 
3,  Plate  I,  Page  11).  The  fore  wings  are  a  chestnut  brown  shaded  with 
purplish  brown.  The  hind  wings  are  whitish  with  pale  brown  margins. 

LIFE  HISTORY 

The  zebra  caterpillar  passes  the  winter  in  the  pupal  stage  in  the 
ground.  The  first  moths  appear  in  May  and  June.  In  moderate  tem- 
peratures the  eggs  hatch  in  about  six  days.  The  worms  feed  four  or  five 
weeks  and  then  change  to  pupae,  in  which  form  they  remain  for  about 
sixty  days.  The  moths  of  the  second  brood  appear  in  late  August  or 
September.  The  second  brood  of  worms  feeds  during  the  fall,  the  change 
from  worm  to  pupa  taking  place  before  winter  sets  in. 

NATURAL  ENEMIES 

This  caterpillar  appears  to  be  especially  attractive  to  the  various 
parasitic  insects  infesting  caterpillars  in  general.  Many  are  killed  by 
fungous  diseases,  while  birds  no  doubt  destroy  them  in  large  numbers. 

2.     LEAF-EATING  BEETLES 

There  is  a  family  of  variously  colored  beetles  of  small  or  moderate 
size,  the  members  of  which  are  called  "leaf-beetles"  because  they  feed 
upon  the  leaves  of  plants  in  both  the  adult  and  larval  stages,  with  a  few 

*Dr.  RH.  Chittenden.  "A  Brief  Account  of  the  Principal  Insect  Enemies  of  the  Sugar  Beet."  Bulle- 
tin No.  43.  Division  of  Entomology.  U.  S   Department  of  Agriculture  (1903). 

88 


Leaf-eating  Beetles  Larger  Sugar  Beet  Leaf-beetle  or  Alkali-beetle 

exceptions  where  the  larvae  are  root  feeders.    The  Colorado  potato-beetle 
is  the  best  known  representative  of  this  family. 

Several  leaf-beetles  feed  upon  sugar  beets  and  under  certain  con- 
ditions do  considerable  damage  to  the  crop.  The  principal  species  of 
this  family,  together  with  other  leaf-eating  beetles  attacking  sugar  beets 
in  the  Great  Plains  area,  are  discussed  in  the  following  pages. 

(a)     LARGER  SUGAR  BEET  LEAF-BEETLE  OR  ALKALI-BEETLE 

(Figs.  1  to  5,  Plate  VII,  Page  23) 

In  Northern  Colorado  this  beetle  is  known  as  the  "alkali-beetle" 
or  "alkali-bug",  from  the  fact  that  it  breeds  most  freely  on  the  weeds 
growing  on  low,  damp  ground  where  the  alkali  is  brought  to  the  surface 
by  seepage.  In  some  other  parts  of  its  range  it  is  known  as  the  "French 
bug". 

NATURE  OF  INJURY 

Both  the  larvae  and  the  adults  damage  sugar  beets.  Injury  usually 
occurs  on  the  border  of  fields  next  to  waste  land  which  is  damp  and  con- 
tains an  excessive  amount  of  alkali.  The  adults  are  very  active  on  the 
wing  and  often  appear  in  swarms  in  the  center  of  fields  or  at  considerable 
distances  from  low  wet  ground.  When  few  in  number  their  work  appears 
very  similar  to  that  of  the  flea-beetles  only  that  the  holes  in  the  leaves 
are  larger.  (See  Fig.  1,  Plate  IV,  Page  17).  In  severe  cases  nothing  but 
a  network  composed  of  the  larger  veins  of  the  leaves  is  left  and  the  leaf 
becomes  brown  and  shriveled. 

METHODS  OF  CONTROL 
Spraying  or  Burning  Weeds 

When  beets  are  planted  near  low,  damp  ground  the  weeds  on  this 
waste  land  should  be  watched  closely  in  early  summer.  If  alkali-beetles 
and  their  larvae  appear  in  numbers  the  weeds  should  be  sprayed  with 
Paris  green  or  straw  should  be  scattered  among  them  and  burned. 

The  destruction  of  the  beetles  and  larvae  at  this  time  will  prevent 
their  migrating  into  the  beet  fields  and  will  also  reduce  the  number  of 
eggs  laid  later. 

Spraying  Crop 

In  case  the  beetles  and  larvae  have  already  begun  to  damage  beets, 
Paris  green  should  be  applied  as  a  spray,  using  4  pounds  to  100  gallons  of 
water.  Many  times  it  happens  that  only  a  small  portion  of  the  field  is 
being  damaged,  making  it  inconvenient  to  use  a  team  and  power  sprayer. 
In  such  case  a  knapsack  sprayer  (See  page  36)  can  be  used  to  advantage. 

Paris  Green  Applied  Dry 

Good  results  have  followed  a  dry  application  of  Paris  green.  If  to 
be  applied  in  this  way  mix  at  the  rate  of  1  pound  of  the  poison  to  10 
pounds  of  low  grade  flour  or  finely  pulverized  air-slaked  lime.  This 
mixture  can  be  dusted  over  the  beets  by  using  a  sack  made  of  coarse  cloth 
or  a  tin  shaker  with  the  bottom  perforated  with  rather  small  holes.  Best 
results  are  secured  if  the  dusting  is  done  early  in  the  morning  when  the 

89 


Larger  Sugar  Beet  Leaf-beetle  or  Alkali-beetle          Western  Beet  Leaf-beetle 

dew  is  still  on  the  beets.  Never  attempt  to  apply  the  dry  poison  when 
the  wind  is  blowing.  Always  spray  or  dust  the  beets  some  distance  be- 
yond where  the  insects  are  feeding. 

DESCRIPTION 
The  Egg 

The  brownish  gray  eggs  (Fig.  3  enlarged  and  Fig.  4  about  natural 
size,  Plate  VII,  Page  23)  are  usually  placed  in  clusters  on  the  under  side 
of  the  leaves  of  the  food  plants.  Russian  thistle  and  saltbush,  both  of 
which  abound  on  alkali  ground,  are  favorite  plants  on  which  to  deposit 
the  eggs. 

The  Larva 

The  young  alkali-bug  is  sluggish  in  its  movements.  In  color  it  is  a 
dirty  gray  at  first,  becoming  darker  with  age.  When  fully  grown  it  ap- 
pears as  in  Figure  1,  Plate  VII,  Page  23.  At  this  time  the  ground  color 
is  an  olive  brown.  The  entire  body  is  covered  with  blunt  tubercles 
each  bearing  several  short,  stiff  hairs.  These  tubercles  are  yellowish  in 
color,  giving  the  larva  a  spotted  appearance. 

The  Pupa 

The  pupa  (Fig.  2,  Plate  VII,  Page  23)  is  what  is  known  as  a  "free 
pupa"  because  the  legs  and  other  parts  of  the  insect  are  encased  separ- 
ately, in  contrast  with  the  pupae  of  the  cutworms  and  other  related  insects. 
The  pupal  stage  is  passed  in  a  small  oval  cell  in  the  soil.  At  first  the  pupa 
is  a  uniform  yellowish  brown  as  shown  in  the  figure,  but  just  before  the 
adult  emerges  the  color  becomes  darker. 

The  Beetle 

The  adult  alkali-beetle  (Fig.  5,  Plate  VII,  Page  23)  often  occurs  in 
swarms.  In  color  it  varies  from  a  light  brownish  yellow  to  almost  black. 
Sometimes  the  wing  covers  are  quite  distinctly  striped,  the  dark  color 
being  concentrated  near  the  center  of  each.  The  figure  represents  an 
intermediate  color  type. 

(b)     WESTERN  BEET  LEAF-BEETLE 

(Fig.  6,  Plate  VII,  Page  23) 

As  the  name  indicates,  this  beetle  is  a  Western  insect.  It  is  more 
common  on  the  Pacific  coast  than  in  the  Rocky  Mountain  regions.  It 
first  attracted  attention  in  the  years  1900  and  1901  in  Oregon.* 

This  beetle  (Fig.  6,  Plate  VI  I,  Page  23)  is  very  similar  to  the  "larger 
sugar  beet  leaf -beetle"  in  coloring  but  is  only  slightly  more  than  one-half 
as  large.  Its  habits  appear  to  be  similar  to  those  of  the  preceding  species. 

NATURE  OF  INJURY 

The  only  cases  known  to  the  writer  where  this  beetle  has  injured 
sugar  beets  have  been  near  low,  damp  ground,  the  beetles  alone  damaging 
the  crop.  The  early  stages  have  not  been  observed  by  the  writer. 

*Dr.  F.  H.  Chittenden,  "A  Brief  Account  of  the  Principal  Insect  Enemies  of  the  Sugar  Beet."  Bulle- 
tin No.  43.  Division  of  Entomology.  U.  S.  Department  of  Agriculture  (1903). 

90 


Western  Beet  Leaf-beetle  Flea-beetles 

METHODS  OF  CONTROL 

The  same  control  measures  employed  against  the  preceding  species 
should  be  used  in  case  this  insect  attacks  sugar  beets  in  sufficient  num- 
bers to  damage  the  crop. 

(c)     FLEA-BEETLES 

The  individuals  of  one  group  of  leaf-beetles  are  characterized  by  hav- 
ing the  joint  of  the  hind  legs  next  to  the  body  much  enlarged.  This 
enables  them  to  jump  long  distances.  The  habit  these  beetles  have  of 
making  sudden  leaps  whenever  disturbed  suggested  the  popular  name 
"flea-beetle"  which  is  applied  to  the  members  of  this  group. 

Most  flea-beetles  are  small,  but  some  species  are  of  moderate  size. 
The  color  is  variable,  some  species  being  dull  black  or  brown;  others  are 
shining  black,  often  with  a  metallic  sheen;  some  are  deep  shining  blue; 
while  in  others  parts  of  the  insect  are  red  or  yellow  or  striped. 

These  active  little  insects  are  familiar  objects  to  every  person  en- 
gaged in  either  gardening  or  farming,  appearing  in  swarms  on  crops  dur- 
ing spring  and  early  summer.  Several  species  attack  sugar  beets,  often 
threatening  serious  damage. 

NATURE  OF  INJURY 

The  work  of  flea-beetles  is  quite  characteristic.  The  leaves  of  the 
plants  attacked  are  eaten  full  of  small  holes  popularly  known  as  "shot 
holes"  (Fig.  1,  Plate  IV,  Page  17).  The  leaves  of  the  seedling  beets  are 
sometimes  completely  destroyed.  In  severe  cases  the  plants  may  be 
killed.  Usually,  however,  plants  which  appear  dead  will  put  forth  new 
leaves  in  the  course  of  a  week  or  ten  days. 

METHODS  OF  CONTROL 
Destroy  Weeds 

Flea-beetles,  in  both  the  adult  and  larval  stages,  feed  upon  many  of 
our  common  weeds.  Clean  culture,  especially  keeping  down  all  weeds 
along  fence  rows  and  ditch  banks,  will  effectively  check  the  multiplica- 
tion of  this  pest.  Poverty-weed  is  a  favorite  food  plant  of  the  banded 
flea-beetle.  (See  page  92). 

Spraying 

Beets  are  usually  attacked  while  still  quite  small.  For  this  reason 
spraying  is  seldom  advisable,  since  the  plants  will  often  be  stripped  of 
their  leaves  before  the  beetles  have  eaten  enough  poison  to  kill  them. 

Scattering 

The  beetles  are  easily  disturbed  and  the  swarms  readily  scattered 
either  by  the  hand  labor  while  thinning  or  by  the  cultivator  in  cultivating. 
In  case  the  beetles  appear  in  a  field  before  the  beets  are  thinned,  it  is  al- 
ways advisable  to  disperse  them  before  this  work  is  done.  This  can  be 
accomplished  by  cultivating  the  field.  If  pieces  of  rope  or  strips  of  can- 
vas are  fastened  to  the  frame  of  the  cultivator  so  as  to  drag  on  the  ground 
the  insects  will  be  more  completely  scattered. 

91 


Flea-beetles  Banded  Flea-beetle 

Irrigation 

The  beetles  dislike  damp  ground.  Advantage  can  be  taken  of  this 
fact,  especially  in  dry  years.  If  the  beets  are  irrigated  the  insects  will 
usually  leave  the  field.  The  irrigation  will  stimulate  the  young  beets  so 
that  they  will  outgrow  the  damage  more  quickly  and  completely.  In 
case  irrigation  is  resorted  to  great  care  should  be  exercised  to  prevent 
flooding  the  field  as  flooding  young  beets  is  injurious  to  them. 

Poison 

In  cases  where  the  use  of  poison  is  advisable  Paris  green  mixed  as 
recommended  in  the  control  of  the  alkali-bug  (page  89)  should  be  used. 
If  the  area  to  be  treated  is  not  too  large,  Paris  green  applied  dry,  mixed 
with  ten  parts  of  low  grade  flour,  will  give  very  satisfactory  results, 
especially  if  the  plants  are  small. 

According  to  Dr.  Chittenden,*  Paris  green  mixed  with  Bordeaux 
mixture  gives  better  results  than  the  Paris  green  and  water  spray.  As  a 
rule  spraying  the  upper  surface  is  sufficient,  but  for  some  species  attack- 
ing truck  crops  the  under  surface  must  also  be  sprayed. 

(c-l)     BANDED  FLEA-BEETLE 

(Fig.  2,  Plate  IV,  Page  17) 

About  the  time  early  beets  are  ready  to  block  and  thin,  swarms  of 
banded  flea-beetles  (Fig.  2,  Plate  IV,  Page  17)  often  appear  in  the  fields. 
Seldom  is  the  whole  field  affected  at  one  time,  however.  The  beetles 
being  very  active,  the  same  swarm  may  appear  in  several  places  in  a  field 
within  a  short  time,  thus  causing  considerable  damage.  Poverty-weed 
is  a  favorite  food  plant  of  this  beetle.  Damage  to  beets  is  most  apt  to 
occur  in  fields  where  this  weed  is  growing. 

DESCRIPTION 
The  Egg 

Dr.  Chittenden,  in  the  bulletin  already  referred  to,*  states  that  the 
eggs  are  laid  in  June  and  July.  They  are  about  one-fourteenth  of  an  inch 
long,  elliptical  in  form  and  of  a  light  buff-yellow  color. 

The  Larva 

The  larva  is  a  slender,  whitish  grub.  The  body  is  narrowest  at  the 
head,  gradually  widening  toward  the  opposite  end.  The  extreme  tip  of 
the  body  tapers  abruptly,  ending  in  a  prolonged  process  which  bears 
several  stiff  hairs.  In  this  stage  the  flea-beetles  feed  upon  the  roots  of 
some  crops  and  weeds. 

The  Adult 

The  adult  beetle  (Fig.  2,  Plate  IV,  Page  17)  is  slightly  more  than  one- 
eighth  of  an  inch  in  length.  The  color  is  somewhat  variable.  A  char- 
acteristic marking  is  the  yellow  stripe  on  each  wing  cover.  The  figure 
represents  one  of  the  darker  colored  individuals. 

M    M  *%  *rVH-'  Chittenden.  "A  Brief  Account  of  the  Principal  Insect  Enemies  of  the  Sugar  Beet,"  Bull*. 
tin  No.  43.  Division  of  Entomology.  U.  S.  Departnwnt  s>{  Agriculture  (1903). 

92 


Banded  Flea-beetle 
Potaio  Flea-beetle  Three-spotted  Flea-beetle 

LIFE  HISTORY 

The  life  history  of  this  beetle  is  imperfectly  known.  It  is  thought 
that  the  winter  is  passed  in  the  larval  stage  only.  The  adults  are  most 
numerous  in  June  and  July,  during  which  months  mating  and  egg  laying 
take  place.  There  is  no  positive  evidence  of  a  second  brood. 

(c-2)     POTATO  FLEA-BEETLE 

(Fig.  5,  Plate  IV,  Page  17) 

Not  infrequently  swarms  of  the  potato  flea-beetle  appear  in  fields  of 
sugar  beets,  causing  considerable  damage  to  small  areas.  At  such  times 
the  injury  to  the  crop  is  similar  in  every  way  to  that  caused  by  the  striped 
flea-beetle  and  the  same  remedies  should  be  applied. 

This  insect's  liking  for  potatoes  is-  indicated  by  its  common  name 
"potato  flea-beetle,"  while  its  habit  of  attacking  cucumbers  and  related 
plants  suggested  the  second  part  of  its  scientific  name,  "cucumeris." 

DESCRIPTION 
The  Larva 

The  larvae  are  small,  whitish  grubs  which  feed  in  the  roots  of  several 
common  wild  plants  all  belonging  to  the  same  family  as  the  potato.  The 
roughened  condition  of  potatoes  known  as  "pimply"  potatoes  is  caused 
by  the  larvae  burrowing  into  the  tubers. 

The  Adult 

The  adult  beetles  (Fig.  5,  Plate  IV,  Page  17)  are  a  dull  black  with 
the  exception  of  the  legs  and  antennae,  which  are  yellowish.  The  wing 
covers  are  clothed  with  very  fine  hairs  and  their  surface  is  covered  with 
small  punctures  which  are  arranged  in  rows.  The  thorax  has  a  deep, 
curved  depression  across  the  posterior  margin,  as  shown  in  the  figure. 
The  small  outline  drawing  at  the  left  of  the  figure  is  the  natural  size  of 
the  adult. 

LIFE  HISTORY 

The  eggs  are  deposited  on  the  roots- of  the  host  plants  during  May 
and  June  by  the  adult  beetles,  which  have  spent  the  winter  in  hibernation 
under  dead  leaves  and  other  trash  along  ditch  banks,  fence  rows  and 
roadsides. 

The  larvae  tunnel  into  the  roots  of  the  host  plants,  where  they  feed 
until  fully  grown.  The  mature  larvae  form  small,  oval  cells  in  the  soil, 
near  the  roots  of  the  plants  within  which  they  fed,  and  change  to  pupae. 

(c-3)     THREE-SPOTTED  FLEA-BEETLE 

(Fig.  6,  Plate  IV,  Page  17) 

The  three-spotted  flea-beetle.  (Fig.  6,  Plate  IV,  Page  17)  is  conspicu- 
ous in  beet  fields  in  early  spring  mainly  because  of  its  size  and  coloring. 
It  is  one  of  the  largest  flea-beetles  and  is  readily  distinguished  by  the 
yellowish-red  thorax  bearing  three  black  spots. 

Lamb's-quarters  and  related  plants,  such  as  Russian  thistle  and  sugar 
beets,  appear  to  be  favorite  food  plants  of  this  species. 

Seldom,  if  ever,  does  this  beetle  occur  in  great  enough  numbers  to 
require  the  application  of  remedial  measures. 

93 


Spinach  Carrion-beetle 
(d)  SPINACH  CARRION-BEETLE 

(Figs.  10  and  11,  Plate  VII.  Page  23) 

The  spinach  carrion-beetle  belongs  to  a  family  of  insects  the  greater 
part  of  whose  members  feed  upon  decaying  animal  matter.  These 
beetles  are  common  objects  under  the  carcasses  of  dead  animals  lying  on 
the  ground. 

A  few  species  of  this  family,  however,  feed  upon  vegetable  matter, 
and  some  on  fungi,  while  others,  like  the  species  under  discussion  and 
its  near  relative,  the  black  carrion-beetle  (Schwarze  Aaskafer)  of  Ger- 
many, feed  upon  sugar  beets  and  other  crops  and  upon  field  weeds. 

From  field  observations  it  seems  quite  probable  that  the  growing  of 
sugar  beets  is  not  responsible  for  the  presence  of  this  pest  in  a  neighbor- 
hood, but  that  its  presence  is  due  to  some  of  its  favorite  host  plants  being 
in  the  vicinity. 

The  following  plants  make  up  the  menu  of  this  beetle:  Lamb's- 
quarters,  green-berried  nightshade,  spinach,  and  sugar  beets.  Squash 
and  pumpkin  vines  are  sometimes  damaged.  The  adults  also  feed  upon 
alfalfa. 

If  none  of  the  weeds  upon  which  it  feeds  are  growing  in  a  neighbor- 
hood the  spinach  carrion-beetle  is  not  apt  to  occur  in  injurious  numbers. 

NATURE  OF  INJURY 

Both  the  adult  beetles  and  the  larvae  feed  upon  sugar  beets.  The 
edges  of  the  leaves  are  eaten,  the  injury  being  quite  characteristic  in  its 
appearance.  According  to  Prof.  R.  A.  Cooley,*  the  gnawed  margins  of 
the  leaves  are  ragged,  often  showing  a  thin  projection  of  crushed  tissue. 

Injury  to  sugar  beets  most  often  occurs  near  roadsides,  ditch  banks, 
fence  rows,  and  grain  and  alfalfa,  from  which  the  insects  migrate  into  the 
beet  fields. 

Sugar  beets  are  seldom  injured  after  they  have  attained  any  size. 
The  greatest  damage  occurs  about  blocking  and  thinning  time,  when 
many  plants  may  be  completely  gnawed  off. 

METHOD  OF  CONTROL 
Clean  Culture 

Much  can  be  done  to  control  this  pest  by  destroying  the  weeds  upon 
which  it  feeds.  However,  the  work  should  not  end  here.  The  beetles 
hibernate  in  the  soil  along  ditches,  fence  rows  and  roadsides.  If  all  weeds 
are  burned  from  these  waste  lands  and  the  soil  thoroughly  disced  or 
plowed  in  the  fall,  few  beetles  will  select  these  bare  spaces  for  hibernation. 
If  the  weeds  and  trash  are  left,  these  places  are  inviting  hibernating 
grounds,  especially  if  a  few  of  the  host  plants  already  mentioned  are 
growing  on  them. 

Poisoned  Bait 

In  the  article*  already  referred  to,  Prof.  Cooley  states  that  the 
poisoned  bran  mash  so  effective  in  the  control  of  cutworms  (See  "Kansas 
Mixture,"  page  39)  is  very  effective  against  the  carrion-beetle  when 

*"Spinach  Carrion-beetle."  Journal  of  Economic  Entomology.  Vol.  10.  No.  1   (1917). 

94 


Spinach  Carrion-beetle 

spread  on  waste  land,  about  ditches  and  fields.  As  the  beetles  and  larvae 
feed  principally  at  night  the  poisoned  bait  to  be  most  effective  should 
be  put  out  late  in  the  day. 

DESCRIPTION 
The  Egg 

The  eggs,  which  are  laid  in  the  soil,  vary  from  almost  spherical  to 
oval  in  form.  The  size  is  also  variable.  The  smaller  ones  are  about  ^\ 
of  an  inch  long  and  the  larger  ones  fa  of  an  inch  long.  The  color  is  a 
creamy  white,  and  the  surface  is  polished  and  glistening.  Prof.  Cooley 
has  observed  that  the  eggs  increase  in  size  after  being  laid. 

The  Larva 

The  newly  hatched  larva  is  about  y6  of  an  inch  long  and  black  in 
color.  When  fully  grown  the  larva  appears  as  shown  in  Figure  1 1 ,  Plate 
VII,  Page  23.  The  color  is  a  shining  black.  The  head  of  the  insect 
represented  by  the  figure  is  bent  downward,  making  it  appear  as 
though  the  first  segment  of  the  thorax  were  the  head.  The  young  car- 
rion-beetles are  flat,  and  the  body,  which  is  composed  of  plates  each^ 
terminating  in  an  acute  angled  corner  at  each  side,  has  the  appearance' 
of  being  notched  on  the  margin. 

The  Pupa 

The  pupa  is  white  and  soft.  The  legs,  antennae  and  wings  are  free. 
At  the  sides  of  the  body  there  are  several  long  hairs  and  at  the  tip  are 
two  fleshy  prongs  also  terminated  by  long  hairs. 

The  Adult 

The  adult  beetles  (Fig.  10,  Plate  VII,  Page  23)  are  uniformly  dull 
black.  The  wing  covers  are  ribbed  lengthwise.  The  Latin  name  of  the 
beetle,  " bituberosa, "  meaning  "with  two  tubercles,"  was  suggested  by 
the  tubercles  at  the  end  of  the  two  outside  ridges. 

LIFE  HISTORY 

Egg  laying  begins  about  the  middle  of  May  and  continues  until 
nearly  the  middle  of  July.  The  females  seem  to  prefer  moist  soil  as  a 
place  to  deposit  their  eggs,  which  are  laid  from  one  to  two  inches  below 
the  surface.  Prof.  Cooley  reports  as  high  as  75  eggs  from  one  female, 
the  average  of  several  being  39.  The  eggs  hatch  in  from  three  to  six 
days. 

The  larval  stage  lasts  about  24  days,  at  the  end  of  which  time  the  full 
grown  larva  enters  the  ground,  forms  an  oval  cell  and  pupates.  The 
pupal  stage  lasts  23  to  26  days,  the  insect  completing  its  development 
from  the  egg  to  the  adult  in  about  55  days. 

After  emerging  from  the  pupae  the  adults  spend  the  remainder  of  the 
season  in  the  soil,  coming  out  occasionally  to  feed.  They  spend  the  winter 
in  hibernation  about  the  margins  of  fields,  on  ditch  banks  and  roadsides, 
coming  forth  as  soon  as  the  frost  leaves  the  ground  in  the  spring.  There 
is  no  evidence  of  more  than  one  brood  each  season. 

95 


Blister-beetles 

(e)    BLISTER-BEETLES 

(Figs.  8,  9,  12  and  13,  Plate  VII,  Page  23) 

In  nearly  all  lists  of  insects  attacking  the  sugar  beet  mention  is  made 
of  several  .species  of  blister-beetles.  The  economic  status  of  some  of  our 
common  species  is  difficult  to  determine,  as  the  larvae,  by  destroying 
grasshopper  eggs,  render  a  real  service  to  agriculture,  while  the  adult 
beetles  damage  certain  crops  by  feeding  upon  their  leaves. 

A  powder  made  of  the  dried  bodies  of  the  adult  beetles  is  used  in 
the  treatment  of  certain  diseases  and  injuries.  When  applied  to  the  flesh 
in  a  paste  form  blisters  are  produced.  This  led  to  the  beetles  being 
called  blister-beetles.  The  powder  made  from  the  dried  bodies  of  a 
European  species  is  known  in  the  commercial  world  as  Spanish-fly. 

NATURE  OF  INJURY 

The  injury  to  crops  (which  is  the  result  of  the  feeding  of  the  adult) 
is  similar  to  that  caused  by  other  leaf-eating  beetles. 

These  beetles  are  strong  fliers,  often  appearing  in  swarms  on  sugar 
beets,  potatoes  and  other  crops,  where  they  feed  most  ravenously  for  a 
time.  Disappearing  as  suddenly  as  they  come,  they  leave  only  the  riddled 
remains  of  the  crop. 

At  such  times  applications  of  poisons  are  of  little  avail  because  of 
the  great  numbers  of  beetles  and  because  of  their  voracity.  Only  the 
promptest  action  and  most  thorough  application  of  whatever  remedies 
are  employed  against  them  will  be  effective. 

METHODS  OF  CONTROL 
Poison 

As  already  stated,  the  use  of  poison  is  seldom  effective.  If  poison 
is  used,  2  to  1\  pounds  of  Paris  green  or  4  to  5  pounds  of  dry  arsenate  of 
lead,  or  8  to  10  pounds  of  arsenate  of  lead  paste,  should  be  used  in  the 
quantity  of  water  necessary  to  spray  one  acre.  This  varies  from  50  to 
100  or  125  gallons  in  the  different  types  of  sprayers. 
Mechanical  Measures 

As  the  beetles  are  very  active  and  readily  put  to  flight,  driving  them 
from  a  field  is  often  the  most  effective  means  of  preventing  losses.  This 
can  be  done  by  several  persons,  armed  with  brush  or  small  branches  of 
of  trees,  driving  the  beetles  ahead  of  them.  Always  work  in  ope  direc- 
tion, taking  as  wide  a  strip  across  the  field  as  possible,  and  going  with  the 
wind. 

According  to  Dr.  Chittenden*,  a  windrow  of  dry  straw  or  hay  placed 
along  one  side  of  the  field  can  be  burned  after  the  beetles  have  been  driven 
onto  it,  thus  destroying  them. 

When  small  areas  or  gardens  are  attacked  the  beetles  can  sometimes 
be  knocked  into  pans  containing  a  small  quantity  of  water  covered  with 
a  thin  film  of  kerosene.  This  method  'is  not  suited  to  large  fields. 

When  the  beetles  are  not  very  numerous  they  can  be  dispersed  and 
serious  damage  prevented  by  using  the  cultivator  equipped  as  suggested 
for  scattering  flea-beetles,  i.  e.,  with  pieces  of  rope  or  strips  of  canvas 
attached  to  the  frame  so  as  to  drag  on  the  plants. 

*"A  Brief  Account  of  the  Principal  Insect  Enemies  of  the  Sugar  Beet."  Bulletin  No.  43.  Division  ot 
Entomology.  U.  S.  Department  of  Agriculture  (1903). 

96 


Blister-beetles 
DESCRIPTION  AND  LIFE  HISTORY 

The  blister-beetles  are  especially  interesting  because  of  the  feeding 
habits  of  their  larvae  and  because  of  the  fact  that  they  pass  through  more 
stages  in  the  course  of  their  development  than  any  of  the  other  beetles 
discussed  in  this  Bulletin.  There  are  six  stages,  the  egg,  three  larval, 
the  pupal  and  the  adult. 

Mention  has  already  been  made  of  the  fact  that  the  larvae  of  some 
species  feed  upon  grasshopper  eggs.  The  seasonal  history  of  these  may 
be  summarized  as  follows: 

The  Egg 

The  eggs,  which  are  small  and  oval  in  form,  are  very  delicate.  They 
are  deposited  in  loose  clusters  in  holes  in  the  ground  which  have  been 
excavated  by  the  female  blister-beetle.  After  the  eggs  are  laid  they  are 
covered  with  loose  soil  which  the  beetle  scratches  over  them  with  her  feet. 

The  places  chosen  for  egg  laying  are  just  those  warm  sunny  spots 
chosen  by  the  female  grasshopper  for  the  same  purpose.  Thus  we  see 
that  the  newly  hatched  blister-beetle  finds  an  abundance  of  food  close 
at  hand  when  it  emerges  from  the  egg. 

The  First  Larval  Stage 

When  the  larva  escapes  from  the  egg  its  head  is  large  and  the  jaws 
are  well  developed.  Its  legs  are  comparatively  long  and  the  body  slender. 

As  soon  as  the  body  walls  become  hardened  by  exposure  to  the  air 
the  active  larva  starts  in  search  of  a  grasshopper  egg-pod.  When  one  is 
found  the  larva  gnaws  its  way  into  it  and  begins  feeding  upon  the  eggs. 

At  the  end  of  its  first  meal  of  uncooked  omelet,  which  may  last  for 
three  or  four  days,  the  larva  spends  the  next  few  days  resting,  and  about 
the  eighth  day  after  beginning  to  feed  the  first  molt  takes  place  and  the 
second  larval  stage  begins. 

The  Second  Larval  Stage 

In  this  stage  the  body  is  much  more  robust  and  the  legs  are  much 
shorter  than  before.  After  feeding  for  about  a  week  another  molt  takes 
place. 

The  legs  and  mouth  are  now  rudimentary  and  the  body  resembles 
that  of  the  white  grub. 

After  about  six  or  seven  days  the  skin  is  once  more  shed  and  what  is 
known  as  the  ultimate  stage  of  the  second  larva  is  begun.  In  this  stage 
the  larva  feeds  more  voraciously. 

After  a  week  of  almost  continuous  feasting  the  larva  leaves  the  re- 
mains of  its  repast  and  burrows  a  short  distance  into  the  soil,  where  a 
smooth  cell  is  formed. 

Within  this  cell  another  change  takes  place.  About  the  third  or 
fourth  day  the  skin  splits  over  the  head  and  is  gradually  worked  backward 
but  is  not  entirely  shed.  The  mouth  and  legs  are  now  quite  rudimentary, 
being  represented  by  small  tubercles.  The  skin  becomes  quite  rigid  and 
takes  on  an  orange  yellow  color  (Fig.  12,  Plate  VII,  Page  23).  This  is 
the  pseudopupa  or  coarctate  larva. 

The  winter  is  spent  in  this  form.  In  the  spring  the  hard  coarctate 
larval  skin  is  cast  off  and  the  third  larval  form  appears. 

97 


Blister-beetles  Grasshoppers 

The  Third  Larval  Stage 

In  this  stage  (Fig.  13,  Plate  VII,  Page  23)  the  larva  is  robust  of  body, 
and  while  the  mouth  parts  and  legs  are  well  developed,  it  does  not  appear 
to  feed. 

After  burrowing  about  in  the  soil  for  a  time  the  third  larva  changes 
to  the  pupa. 

The  Pupa 

The  pupa  is  white  at  first,  becoming  darker  as  the  time  for  the 
emergence  of  the  adult  approaches.  The  legs,  wings  and  antennae  are 
free,  as  in  the  pupa  of  the  alkali-beetle. 

The  pupal  stage  lasts  from  five  to  six  days,  when  the  adult  beetle 
appears. 

The  Adult 

The  adult  blister-beetles  are  slender,  rather  soft  bodied  insects.  In 
fall  they  are  common  objects  on  the  flower  clusters  of  goldenrod  and 
other  plants. 

The  black  blister-beetle  (Fig.  8,  Plate  VII,  Page  23)  feeds  upon 
Russian  thistle  and  goldenrod  blossoms,  as  well  as  potatoes  and  other 
crops. 

The  ash-gray  blister-beetle  (Fig.  9,  Plate  VII,  Page  23)  is  quite 
common  in  alfalfa  fields  in  Northern  Colorado,  where  it  feeds  upon  the 
leaves  of  the  alfalfa. 

3.     GRASSHOPPERS 

During  the  early  seventies  the  rich  prairie  soils  of  western  Minnesota 
attracted  many  homesteaders,  so  that  by  the  summer  of  1876  (which  is 
known  as  one  of  the  worst  grasshopper  years  in  the  history  of  American 
agriculture),  the  vast  expanse  of  these  prairies  was  dotted  with  claim 
shanties,  tree  claims  and  green  fields. 

The  first  of  June  of  this  memorable  summer  all  crops  gave  promise  of 
a  bountiful  harvest.  Then  vague  rumors  of  great  hordes  of  Rocky 
Mountain  locusts,  which  were  destroying  crops  to  the  southwest,  caused 
much  apprehension  among  the  settlers,  many  of  whom  had  spent  their 
last  dollar  in  the  planting  of  their  crops,  fully  expecting  the  harvest  to  be 
sufficient  for  their  future  needs. 

About  June  20th  great  swarms  of  hoppers  began  flying  over,  coming 
from  the  northwest  and  always  traveling  to  the  southeast.  At  times  the 
swarms  were  so  large  and  the  hoppers  flew  in  such  dense  bodies  that  one 
could  look  directly  toward  the  sun  without  hurting  the  eyes.  The  light 
was  dimmed  as  though  a  thin  cloud  obscured  the  sun. 

The  suspense  of  the  homesteaders  had  almost  reached  the  breaking 
point  when  the  wind  changed  and  the  long  dreaded  thing  happened. 
Suddenly,  about  ten  o'clock  in  the  forenoon  of  July  5th  people  were 
startled  by  a  loud,  rushing  sound  like  that  of  an  approaching  storm. 
Upon  going  outside  a  sight  long  to  be  remembered  met  their  eyes. 

From  the  sky,  like  huge  snow  flakes,  millions  of  Rocky  Mountain 
locusts  were  dropping  to  earth.  This  living  shower  lasted  for  about 
half  an  hour,  when  it  ceased  as  suddenly  as  it  began. 

98 


Grasshoppers 

The  ground  was  literally  covered  with  a  seething,  kicking  mass  of 
hoppers  three  to  four  deep.  Gradually  this  struggling  horde  became 
quiet,  resting  in  regularly  arranged  rows  and  layers.  In  this  position 
they  remained  for  about  four  hours,  when  the  work  of  devastating  the 
fields  began.  Their  work  was  rapid  and  thorough  and  the  destruction 
complete. 

The  writer's  father  describes  the  work  of  these  hoppers  in  a  corn 
field  as  follows : 

"After  having  rested  for  about  four  hours  those  hoppers  next  to  the 
corn  stalks  began  to  feed  upon  them  near  the  ground.  As  this  weakened 
them  the  stalks  fell  and  were  immediately  attacked  by  other  hoppers. 
Stalk  after  stalk  fell,  until  about  sundown,  when  feeding  ceased  for  the  day, 
less  than  a  hundred  stalks  remained  standing  in  a  4£  acre  field.  When 
the  hoppers  left  this  field  not  a  vestige  of  the  crop  remained  excepting  the 
stumps  of  the  corn." 

Garden  truck,  with  the  exception  of  peas,  was  also  completely  de- 
stroyed. Root  crops  such  as  beets  and  turnips  were  eaten  leaf  and  root. 
Where  each  plant  stood  only  a  hole  in  the  ground  remained.  As  they 
devoured  these  roots  the  ravenous  hoppers  fought  for  a  place  until  their 
bodies  and  extended  legs  resembled  a  bundle  of  sticks  set  on  end  in  a 
small  bowl. 

The  third  day  the  hoppers  rose  and  started  in  a  southeasterly  direc- 
tion. They  disappeared  as  suddenly  as  they  came,  leaving  only  bare 
ground  and  disheartened  farmers  behind  over  an  area  one  hundred  miles 
square. 

Nothing  more  was  seen  of  the  hoppers  until  early  August,  when  a 
second  but  smaller  swarm  settled  on  the  cropless  country  covered  by  the 
earlier  one.  This  second  swarm  found  little  but  the  prairie  grasses  to 
feed  upon.  However,  this  furnished  sufficient  food  for  them  until  they 
had  honeycombed  fields  and  prairie  with  their  egg  pods. 

The  following  spring  the  whole  country  was  a  hopping  mass  of  young 
Rocky  Mountain  locusts.  Then  began  the  fight  to  destroy  this  growing 
army  and  save  what  crops  had  been  sown. 

All  the  young  hoppers  traveled  in  one  direction.  Whichever  way 
they  started  in  the  morning  was  the  direction  for  the  day.  While  they 
were  still  small,  trenches  were  dug  in  front  of  them  into  which  they  fell 
and  in  which  they  were  buried. 

The  hopper  dozer  played  its  part  in  the  fight  against  the  young  hop- 
pers as  they  became  larger  and  more  active.  By  constant  fighting  some 
crops  were  partially  saved,  at  an  enormous  cost  of  time  and  hard  work. 

About  the  first  of  June  the  hoppers,  having  acquired  wings,  took 
flight  for  parts  unknown. 

With  the  exception  of  very  local  outbreaks,  which  have  been  quickly 
brought  under  control,  the  Rocky  Mountain  locust  has  never  since  ap- 
peared within  the  bounds  of  the  vast  territory  devastated  during  1875  to 
1877.  In  those  parts  of  its  range  where  it  was  most  numerous  during 
these  years  it  is  almost  unknown  at  the  present  time. 

Thus  one  of  the  most  destructive  insects  of  the  Western  Hemisphere 
came,  devastated  vast  areas  of  crops  and  passed  on,  never  since  to  appear 
in  anything  like  the  same  numbers  in  any  part  of  its  former  range. 

99 


Grasshoppers 

While  the  Rocky  Mountain  locust  has  almost  ceased  to  be  a  pest, 
there  are  several  other  species  of  grasshoppers  which  frequently  occur  in 
great  numbers  and  do  much  damage  to  crops  within  restricted  areas. 
Three  of  these  species — the  two-lined  hopper,  the  differential  hopper  and 
the  red-legged  locust — are  worthy  of  special  mention. 

(a)     TWO-LINED  HOPPER 

(Figs.  9,  10  and  11,  Plate  IV,  Page  17) 

The  two-lined  hopper,  together  with  the  two  following  species,  often 
occurs  in  large  numbers  in  the  Great  Plains  area. 

It  is  easily  distinguished  from  our  other  injurious  species  by  the  two 
light  lines  beginning  at  the  eyes  and  extending  along  the  back  and  meet- 
ing at  the  tip  of  the  wings. 

The  females,  one  of  which  is  shown,  natural  size,  in  Figure  10,  Plate 
IV,  Page  17,  are  larger  than  the  males.  The  color  of  both  sexes  is  yellow- 
ish or  tan  color,  with  darker,  almost  black  markings.  Some  of  the  males 
are  much  darker  than  the  females,  there  being  very  little  yellow  visible 
on  these  dark  individuals.  However,  the  light  lines  mentioned  above 
are  always  clearly  discernible. 

(b)     DIFFERENTIAL  HOPPER 

(Figs.  12  and  13,  Plate  IV,  Page  17) 

Many  times  the  differential  hopper  outnumbers  the  preceding  one. 
Since  the  passing  of  the  Rocky  Mountain  locust  it  has  been  one  of  the 
principal  injurious  forms  in  the  Great  Plains  area. 

This  hopper  occurs  in  two  colors,  with  many  intermediate  shades. 
Figure  12,  Plate  IV,  Page  17  represents  a  male  of  the  light  or  yellow 
phase,  while  Figure  13,  Plate  IV  represents  the  opposite  color  extreme. 

In  size  this  hopper  resembles  its  near  relative,  the  two-lined  hopper. 
However,  in  all  its  color  variations,  it  can  be  distinguished  from  the  two- 
lined  hopper  by  the  lack  of  the  two  pale  lines  on  the  back. 

(c)     RED-LEGGED  LOCUST 

(Figs.  14  and  15,  Plate  IV,  Page  17) 

The  red-legged  locust  may  be  taken  as  representative  of  a  group  of 
small  or  medium  sized  species  which  have  in  the  past  been  responsible 
for  widespread  damage  to  crops. 

In  general  appearance  and  size  the  red-legged  locust  resembles  the 
Rocky  Mountain  locust  already  referred  to,  the  lesser  migratory  locust, 
and  the  California  devastating  locust. 

It  is  very  difficult  to  give  a  popular  description  of  this  grasshopper 
that  will  make  it  possible  for  one  not  trained  in  entomology  to  distinguish 
it  from  the  other  three  species  mentioned  in  the  preceding  paragraph. 

Figure  14,  Plate  IV,  Page  17  represents  an  average  male,  natural 
size.  The  females  are  somewhat  larger.  The  color  of  this  hopper  is 
variable,  being  brownish,  shaded  with  almost  black  in  the  darker  indi- 
viduals. In  the  light  individuals,  the  lighter  portions  are  yellowish 
brown. 

The  slender  part  of  the  hind  legs  is  usually  reddish,  although  in  some 
specimens  it  is  yellowish  or  even  pale  green. 

100 


Grasshoppers 

NATURE  OF  GRASSHOPPER  INJURY 

Grasshoppers  belong  to  that  group  of  leaf -feeding  insects  which  bite 
their  food.  The  crops  attacked  are  often  completely  defoliated,  and  in 
the  case  of  root  crops  such  as  sugar  beets,  turnips  and  others  the  roots 
are  often  eaten  as  well.  The  crowns  of  sugar  beets  are  often  completely 
destroyed  and  as  a  consequence  the  beets  soon  die,  as  they  cannot  develop 
new  leaves. 

Young  alfalfa  is  often  destroyed  by  grasshoppers,  especially  where 
the  ripening  of  the  grain  used  as  a  nurse  crop  forces  them  to  seek  other 
green  food. 

When  attacking  oats,  grasshoppers  have  the  peculiar  habit  of  gnaw- 
ing off  the  kernels,  which  they  seldom  if  ever  eat. 

When  other  food  fails,  shade  trees  and  shrubs  are  attacked  and 
stripped  of  their  leaves. 

During  recent  years  grasshopper  injury  has  usually  occurred  near 
wild  land  or  waste  land  about  the  borders  of  fields,  roadsides,  ditch  banks 
and  fence  rows,  which  are  favorite  breeding  grounds  of  all  grasshoppers. 
With  the  passing  of  the  Rocky  Mountain  locust  the  migration  of  large 
swarms  of  grasshoppers  from  long  distances  appears  to  be  a  thing  of  the 
past. 

METHODS  OF  CONTROL 
Kansas  Mixture 

The  most  effective  remedy  employed  in  the  control  of  grasshoppers 
is  the  poisoned  bran  mash  known  as  "Kansas  Mixture, "  which  is  made  of 
the  following  ingredients:' 

Bran 25  Ibs. 

Paris  green < 1|  Ibs. 

Molasses 2  qts. 

Lemons 5 

Water,  about 3  gals. 

It  will  be  noted  that  the  formula  for  use  against  grasshoppers  is 
slightly  different  from  that  given  on  page  39  for  use  against  cutworms. 

How  to  Prepare  the  Mixture 

In  preparing  this  mixture  proceed  in  the  following  manner:  Thor- 
oughly mix  the  bran  and  Paris  green  while  dry  until  the  whole  has  a  uni- 
form greenish  color.  Take  about  two  gallons  of  water  and  add  to  this 
the  molasses  and  lemons  after  the  latter  have  been  finely  ground,  rind  and 
all.  Stir  this  mixture  until  the  molasses  is  completely  dissolved,  then 
pour  it  over  the  bran  and  Paris  green.  Mix  until  evenly  moistened, 
then  add  water  a  little  at  a  time  until  the  mash  is  just  wet  enough  to  stick 
together  well  but  yet  dry  enough  to  crumble  readily  when  being  spread. 

When  to  Apply  the  Mixture 

Grasshoppers  spend  the  night  on  weeds  and  other  plants  well  up 
above  the  ground.  Not  until  after  the  sun  rises  and  they  have  become 
warmed  do  they  become  active  and  begin  feeding.  After  their  night's 
fast  the  hoppers  are  hungry,  so  that  if  the  poisoned  bran  is  scattered 
before  they  begin  feeding  in  the  morning  the  best  results  are  secured.  I-f 

101 


Grasshoppers 

the  mixture  is  put  out  in  the  evening  it  loses  much  of  its  odor  during  the 
night  and  is  less  effective  as  a  result.  When  put  out  after  the  hoppers 
have  filled  up  in  the  morning  they  are  less  hungry  and  do  not  eat  so  freely 
of  the  bait  as  earlier  in  the  morning.  Then  by  the  time  they  are  ready 
for  another  meal  the  sun  has  dried  it  more  or  less,  whicht  makes  it  less 
appetizing. 

Also,  apply  the  remedy  in  the  early  part  of  the  season,  while  the 
hoppers  are  small.  "  It  is  the  early  bird  that  catches  the  worm. "  Like- 
wise it  is  the  early  farmer  that  gets  the  hopper. 

How  to  Apply  the  Mixture 

The  Kansas  Mixture  should  be  thinly  broad-casted  over  the  ground. 
The  most  satisfactory  way  is  to  sow  it  by  hand,  using  the  same  motion 
as  in  sowing  grain  or  grass  seed  by  hand.  Care  should  be  exercised  to 
prevent  leaving  large  lumps  in  the  spreading,  as  these  are  apt  to  be  eaten 
by  live  stock  or  poultry  and  cause  their  death.  The  mixture  made  with 
quantities,  according  to  the  formula  given,  is  sufficient  to  cover  4|  to  5 
acres.  If  thinly  and  evenly  applied  to  this  area  there  is  no  danger  of 
either  live  stock  or  poultry  being  killed  by  feeding  on  treated  land. 

Where  to  Apply  the  Mixture 

The  poisoned  mash  should  be  scattered  on  waste  land,  borders  of 
fields  or  other  places  where  the  hoppers  congregate  for  the  night. 

The  Hopper  Dozer 

During  the  years  1875  to  1877  many  devices  for  destroying  grass- 
hoppers, especially  the  wingless,  young  hoppers,  were  invented  and  cov- 
ered by  patent  rights.  The  inventors  of  some  attempted  to  use  sulphur 
fumes  to  kill  the  hoppers,  others  crushed  them  between  rollers,  and  still 
others  used  the  principle  of  the  vacuum  cleaner  to  suck  the  hoppers  into 
their  machine. 


Fig.  15.     Hopper  Dozer  (After  Chas.  R.  Jones,  Bulletin  No.  233,  Colorado  Agricultural 
Experiment  Station) 

102 


Grasshoppers 

Of  this  assortment  of  mechanical  hopper  killers  only  the  hopper 
dozer  (Fig.  15,  Page  102),  as  we  know  it  today,  has  survived.  This  de- 
vice has  long  been  recognized  as  effective  in  destroying  grasshoppers,  but 
its  usefulness  is  confined  to  low  standing  crops,  mown  meadows,  stubble 
fields  and  relatively  flat  ground.  Where  the  ground  is  rolling  or  hilly  the 
"live  hopper  machine"  takes  the  place  of  the  dozer. 

The  hopper  dozer  consists  of  a  sheet-iron  pan  about  4  inches  deep 
and  12  to  16  feet  long  by  1\  to  3  feet  wide.  This  is  separated  into  com- 
partments by  cross  partitions,  making  the  compartments  about  square. 
These  cross  partitions  are  to  prevent  the  liquid  used  in  the  pan  from  run- 
ning to  either  end  when  the  dozer  is  used  on  slightly  rolling  ground.  This 
pan  is  placed  on  runners  made  of  2x4  or  2x6  lumber.  At  the  back  and 
ends  of  the  pan  is  an  upright  sheet  of  tin  or  oilcloth  2|  or  3  feet  high, 
against  which  the  hoppers  fly  and  are  knocked  or  slide  down  into  the  pan. 

When  in  operation  the  pan  is  partially  filled  with  water  covered 
with  a  thin  film  of  kerosene.  As  the  hoppers  accumulate  in  this  liquid 
they  are  skimmed  off.  If  this  is  not  done  the  falling  insects  are  prevented 
from  becoming  coated  with  the  oil  and  water,  which  is  necessary  in  order 
to  kill  them.  The  dozer  is  drawn  by  horses,  one  hitched  at  either  end. 

A  dozer  of  this  sort  can  be  built  on  the  farm,  and  should  be  constructed 
for  $6.00  to  $7.00  when  normal  prices  prevail. 

The  Live  Hopper  Machine 

This  device,  which  is  of  more  recent  origin  than  the  dozer,  is  espec- 
ially adapted  to  use  on  rolling  or  hilly  land  where  those  devices  which 
employ  liquids  cannot  be  satisfactorily  worked. 

The  live  hopper  machine  consists  of  a  box  about  2  feet  wide,  2  feet 
deep  and  16  feet  long,  with  bottom  and  ends  of  wood,  and  top  and  back  of 
fine  screen.  The  remaining  side  of  the  box  is  partially  closed  by  a  curved 
sheet  iron  or  tin  deflector  about  three  feet  high  and  extending  along  its 
entire  length.  The  deflector  reaches  to  within  about  three  inches  of  the 
bottom  of  the  box,  the  lower  edge  being  curved  backward  into  it.  Just 
in  front  of  this  is  a  narrow  strip  of  tin  fastened  to  the  bottom  of  the  box 
directly  under  the  bent-in  portion  of  the  deflector  and  curved  outward 
and  upward  to  a  height  of  about  six  inches.  Thus  a  curved  mouth  is 
produced  along  the  entire  length  of  the  box.  The  hoppers  flying  against 
the  deflector  slide  down  into  this  mouth.  The  narrow  strip  of  tin  men- 
tioned prevents  the  hoppers  from  escaping  by  hopping  off  of  the  machine 
in  front.  Once  in  the  mouth  of  the  box,  the  light  coming  through  the 
screen  attracts  them  and  the  hoppers  enter  it  in  an  attempt  to  escape, 
and  are  imprisoned. 

At  each  end  of  the  box  is  a  door  which  is  used  in  removing  the  hop- 
pers from  the  machine  after  they  have  been  killed  by  being  sprayed  with 
kerosene. 

The  machine  is  placed  on  runners  and  drawn  by  horses  in  the  same 
manner  as  the  dozer. 

Harrowing  and  Discing 

Even  though  the  hopper  dozer  is  used  and  the  Kansas  Mixture  ap- 
plied, many  grasshoppers  will  reach  maturity  and  many  eggs  will  be  laid 
each  fall.  In  order  fully  to  round  out  the  season's  work  against  the  grass- 

103 


Grasshoppers 

hopper  plague,  all  waste  land  should  be  thoroughly  harrowed  or  disced. 
This  harrowing  and  discing  will  break  up  the  egg  pods  and  scatter  the 
eggs  where  exposure  to  the  air  and  weather  will  destroy  them. 

Many  eggs  will  be  deposited  in  alfalfa  fields.  The  practice  of  reno- 
vating this  crop  with  some  one  of  the  various  makes  of  alfalfa  renovators 
not  only  destroys  many  grasshopper  eggs,  but  benefits  the  crop  as  well. 
Early  spring  or  fall  renovating  is  most  effective  in  destroying  grasshop- 
per eggs. 
Plowing 

Next  to  harrowing  and  disking,  plowing  egg  infested  land  is  one  of 
the  most  effective  cultural  means  of  preventing  hopper  losses.  Plowing 
alone  does  not  destroy  many  of  the  eggs,  but  if  the  soil  is  plowed  to  a 
depth  of  four  to  five  inches  and  the  surface  thoroughly  worked  with  the 
harrow,  a  very  small  proportion  of  the  young  hoppers  will  succeed  in 
making  their  way  to  the  surface. 
Clean  Culture 

Our  injurious  species  of  grasshoppers  prefer  weedy  or  grassy  land  as 
places  to  deposit  their  eggs.  If  all  waste  land  about  fields,  ditches  and 
fences  is  kept  free  of  vegetation,  few  eggs  will  be  deposited  and  adjoining 
fields  will  be  comparatively  free  from  injury. 

Poultry 

Poultry,  if  allowed  to  run  at  large,  will  rid  considerable  areas  of 
grasshoppers.  Turkeys  are  more  valuable  for  this  purpose  then  hens,  as 
they  range  farther  and  spend  more  time  in  the  fields.  A  small  flock  of 
turkeys  is  a  double  source  of  profit  to  the  farmer. 

LIFE  HISTORIES  OF  GRASSHOPPERS 

The  life  histories  of  our  most  injurious  species  of  grasshoppers  are 
very  similar. 

The  mature  females  usually  select  some  dry  sunny  location  covered 
with  a  growth  of  weeds  or  bunches  of  grass  for  depositing  their  eggs.  The 
eggs  arc  deposited  in  holes  in  the  soil  which  are  lined  with  a  glue  like 
substance  secreted  during  egg  laying.  When  this  becomes  hardened  it 
protects  the  eggs  from  excessive  drouth,  moisture,  and  possibly  to  some 
extent,  from  predacious  insects  or  egg  parasites. 

In  making  these  holes  the  female  presses  the  tip  of  her  abdomen, 
armed  with  four  hard,  curved  and  pointed  plates  (See  Figs.  10  and  11, 
Plate  IV,  Page  17),  against  the  soil.  By  alternately  opening  and  closing 
these  plates  the  soil  is  forced  aside. 

When  the  hole  is  filled  with  eggs  it  is  sealed  with  more  of  the  glue- 
like  secretion.  This  egg  cluster  inclosed  within  its  impervious  case  is 
called  an  egg  pod.  Figure  8,  Plate  IV,  Page  17  represents  one  of  these 
egg  pods  removed  from  the  soil.  A  portion  of  the  covering  has  been  re- 
moved near  the  upper  end,  exposing  the  eggs.  The  eggs  are  of  a  yellow- 
ish or  olive  yellow  color,  about  one-fourth  of  an  inch  long,  cylindrical, 
and  slightly  curved.  Most  females  deposit  two  egg  clusters,  the  total 
number  of  eggs  laid  varying  from  50  to  100  or  more. 

All  of  our  injurious  grasshoppers  pass  the  winter  in  the  egg  stage. 
There  are  several  species,  however,  that  hatch  in  the  fall  and  hibernate 
in  an  immature  state,  completing  their  development  the  next  summer. 

104 


Grasshoppers 

Their  presence  about  fields  during  warm  weather  in  winter  is  responsible 
for  many  reports  of  early  hatching  of  grasshopper  eggs. 

Hatching  begins  during  late  May  and  early  June  and  extends  over  a 
considerable  period  of  time.  Those  eggs  deposited  on  sunny,  south 
slopes  and  in  other  protected  locations  hatch  first. 

The  young  grasshoppers  or  nymphs  (Fig.  9,  Plate  IV,  Page  17)  re- 
semble the  adults  but  lack  the  wings  of  the  latter.  During  their  develop- 
ment they  shed  their  skins  several  times.  With  each  molt  they  resemble 
the  adults  more  closely.  Just  before  the  last  molt  they  appear  as  shown 
in  Figure  1,  Plate  V,  Page  19.  At  this  time  the  wings  are  represented 
by  four  pads  on  the  back  of  the  insect. 

During  the  process  of  molting,  grasshoppers  cling  to  some  plant  to 
which  the  cast  skin  often  remains  fastened  for  some  time. 

With  the  last  molt  the  grasshopper  becomes  an  adult  with  fully  de- 
veloped wings.  Mating  soon  takes  place  and  egg  deposition  begins, 
usually,  about  the  middle  of  August  and  continues  until  cold  weather 
kills  the  grasshoppers. 

NATURAL  ENEMIES 
Flesh  Flies 

The  larvae  of  several  species  of  flies  belonging  to  a  family  popularly 
known  as  "flesh  flies"  are  parasitic  upon  grasshoppers. 

Figure  3,  Plate  IV,  Page  17  represents  a  flesh  fly  7  which  was 
reared  from  the  two-lined  hopper.  The  larva  or  maggot  of  this  fly  is 
shown  in  Figure  4,  Plate  IV. 

The  flesh  flies  here  referred  to  are  viviparous,  which  is  to  say  that 
they  give  birth  to  living  maggots  instead  of  laying  eggs. 

Mr.  E.  O.  G.  Kelley*  describes  the  manner  in  which  one  of  these 
flies  places  its  larvae  upon  the  host  hopper  substantially  as  follows : 

While  the  hoppers  are  on  the  wing  the  female  flesh  flies  strike  them 
on  the  under  side  of  the  lower  wing,  at  the  same  time  depositing  a  tiny 
maggot  near  its  margin.  When  struck  the  hopper  drops  to  the  ground. 
The  maggots  were  observed  by  this  author  to  crawl  along  the  margin  of 
the  wing  to  its  base  and  then  to  enter  the  hopper's  body  through  some 
natural  opening  or  tender  tissue.  Once  within  the  hooper  the  maggots 
feed  upon  its  body  fluids  until  mature.  The  hoppers  usually  live  until 
the  maggots  are  nearly  full  grown.  However,  these  parasitized  hoppers 
are  apt  to  be  sluggish  and  inactive  several  days  before  their  vitals  are 
destroyed  and  they  die.  When  mature  the  maggots  leave  the  dead 
hopper,  burrow  into  the  ground  or  conceal  themselves  underneath  trash, 
change  to  pupae  and  later  into  adult  flies. 

The  flesh  flies  are  foremost  in  the  list  of  insect  enemies  of  the  grass- 
hopper and  are  of  the  greatest  value  to  agriculture.     They  seldom  appear 
in  buildings  in  numbers,  being  denizens  of  the  fields  where  their  good 
work  is  done. 
Ground  Beetles 

Several  species  of  beetles  commonly  known  as  ground  beetles  (See 
page  1 30)  are  known  to  feed  upon  grasshopper  eggs  as  well  as  the  grass- 
hoppers, especially  in  their  immature  stages. 

*"A  New  Sarcophagid  Parasite  of  Grasshoppers."  Journal  of  Agricultural  Research.  Vol.  II.  No.  6 
(1914). 

(7)  See  explanation  of  "Reference  Figures,"  page  2. 

105 


Grasshoppers 

The  egg-eating  Amara  (Figs.  20,  21  and  22,  Plate  IX  Page  27)  be- 
longs to  this  family  and  is  of  especial  interest  because  of  the  good  work 
its  larvae  did  in  destroying  eggs  of  the  Rocky  Mountain  locust  in  the 
territories  overrun  by  this  insect  in  1876  and  1877. 

Wherever  grass- 
hopper eggs  are  plen- 
tiful, the  larvae  (Fig. 

20,  Plate  IX,  Page 
27)  of  this  beetle  will 
be   found.     These 
whitish  yellow  grubs 
with  brown   heads 
and  dark  shields  on 
each  segment  of  the 
body  burrow  among 
the  roots  of  grasses 
(Fig.  16,  Page  106), 
where    the  female 
grasshoppers  have 
deposited  their  eggs, 
and  destroy  them  in 
large  numbers. 

The  change  from 
larva  to  pupa  (Fig. 

21,  Plate  IX,  Page 
27)  takes  place  dur- 
ing early  May  and 
the  adult  beetles 
(Fig.  22,  Plate   IX, 
Page  27)  emerge  two 
or  three  weeks  later. 

Blister-beetles 

The  part  which  the  larvae  of  blister-beetles  play  in  the  destruction 
of  grasshopper  eggs  has  been  discussed  on  page  96.  However,  the  good 
work  of  these  larvae  is  partially  offset  by  the  adult  beetles  feeding  upon 
crops. 

Locust  Mites 

The  locust  mite  (Figs.  1,2,  17  and  18,  Plate  V,  Page  19)  is  one  of  the 
most  interesting  as  well  as  important  enemies  of  the  grasshopper.  This 
little  creature,  which  is  closely  related  to  the  "chiggers"  so  common  in 
some  parts  of  the  country,  is  not  an  insect  but  belongs  to  the  same  class 
of  invertebrate  animals  as  the  spider. 

The  animals  of  this  class,  which  includes  the  scorpions,  harvestmen, 
spiders,  mites,  ticks  and  others,  differ  from  the  true  insects  in  having  four 
pairs  of  legs  instead  of  three  pairs  in  the  adult  stage  and  in  having  the 
head  and  thorax  grown  together.  However,  the  immature  stages  often 
have  but  three  pairs  of  legs. 

During  those  years  when  the  Rocky  Mountain  locust  overran  the 
country  west  of  the  Mississippi  river  the  ground  was,  at  times,  almost 
red  with  locust  mites. 


Fig.   16.    Exposed    Grass    Roots,     showing-    Grasshopper 
Eggs  and  Larvae  of  the  Ground  Beetle,   Amara  obesa 


106 


Grasshoppers 

The  adult  female  (Fig.  17,  Plate  V,  Page  19)  deposits  her  eggs,  a  few 
of  which  are  shown  above  the  figure,  in  clusters  of  from  300  to  400.  These 
are  placed  below  the  surface  of  the  soil,  often  to  a  depth  of  1|  to  2  inches. 
The  adult  male,  which  is  smaller  than  the  female,  is  shown  in  Figure  18, 
Plate  V,  Page  19. 

In  due  time  the  minute,  orange-red  larvae,  one  of  which  is  shown 
much  enlarged  in  Figure  2,  Plate  V,  Page  19,  emerge.  These  larvae 
possess  but  three  pairs  of  legs.  However,  they  are  very  active  and  soon 
become  attached  to  a  grasshopper  as  shown  in  Figure  1,  Plate  V,  Page 
19.  Usually  the  young  mites  are  found  under  the  wing  pads  when  there 
are  but  a  few  on  an  individual. 

These  mites  are  sometimes  mistaken  for  the  red  eggs  of  some  parasite. 

The  bodies  of  the  young  locust  mites  become  distended  in  true  tick 
fashion  after  feeding  on  a  grasshopper  and  drop  to  the  ground,  moving 
about  with  difficulty  in  this  condition.  After  secluding  themselves 
under  trash  or  among  the  clods  on  the  surface  of  the  soil  the  change  to  the 
pupa  and  from  the  pupa  to  the  adult  takes  place.  The  adults,  which 
feed  upon  the  eggs  of  grasshoppers,  spend  the  winter  secluded  beneath 
any  object  which  furnishes  protection  from  the  weather. 


Hair  Worms 


The  hair  worms  or  hair 
snakes  (Fig.  17,  Page  107, 
Fig.  18,  Page  108,  and  Fig. 
16,  Plate  IV,  Page  17)  are 
still  believed  by  some  to 
be  animated  horse  hairs. 
Even  those  knowing  the  fal- 
lacy of  this  old  belief  do  not 
always  know  the  relation  of 
these  worms  to  other  living 
creatures.  The  majority  of 
those  hair  or  "Gordian 
worms"  observed  swimming 
about  in  stagnant  pools  or 
the  margins  of  streams  and 
in  irrigation  ditches  belong 
to  the  genus  Gordius. 

The  worms  of  this  group 
are  parasitic  within  insects. 
The  eggs  are  laid  in  water, 
usually  in  the  spring,  and  in 
the  course  of  a  week  or  ten 
days  the  young  worms 
emerge.  They  are  armed 
with  piercing  mouth  parts 
with  which  they  force  their 
way  into  the  body  of  some  insect  where  they  become  encysted  in  its 
muscles.  This  insect  is  in  turn  eaten  by  some  other  within  which  the 
encysted  hair  worm  completes  its  development.  Many  Rocky  Mountain 
locusts  were  destroyed  by  these  worms  during  the  outbreak  of  this  insect 

107 


Fig.   17.    Hair  Worm  escaping  from  a  parasitized 
Ground    Beetle 


Grasshoppers 

in  the  seventies.      Infested  grasshoppers  have  a  pale,  sickly  appearance 

and  are  more  or  less  sluggish  in  their  movements. 

Ground  beetles  are  also  often  infested.     Figure  17,  Page  107  shows 

a  common  species  just  as  the  hair  worm  is  emerging.     Figure  18,  Page 

108  shows  the  worm  after  freeing  itself  from  the  beetle.     Figure  16, 

Plate  IV,  Page  17  repre- 
sents a  mature  male  hair 
worm  taken  from  a  ground 
beetle. 

Birds 

A  discussion  of  the  natural 
enemies  of  the  grasshopper 
would  not  be  complete  with- 
out mention  of  some  of  the 
many  birds  which  assist  in 
holding  this  pest  in  check. 

The  list  of  birds  which 
render  a  real  service  to  agri- 
culture by  destroying  grass- 
hoppers includes  some  which 
are  not  in  very  good  stand- 
ing because  of  occasional 
damage  to  crops  or  raids 
upon  the  poultry  yard  or 
orchard,  and  because  of  a 
lack  of  knowledge  of  their 
feeding  habits  throughout 
the  entire  year. 

Generally  speaking,  all  owls  are  looked  upon  as  undesirables  and 
as  the  legitimate  prey  of  the  hunter.  As  a  matter  of  fact,  with  the 
exception  of  the  great  horned  owl,  these  birds  do  far  more  good  than 
harm.  The  occasional  young  chicken  or  turkey  which  they  steal  is  small 
pay  for  the  many  mice,  ground  squirrels  and  other  injurious  rodents 
which  they  kill,  to  say  nothing  of  the  grasshoppers  which  some  destroy. 

The  long-legged  burrowing-owl,  which  inhabits  deserted  prairie  dog 
burrows,  feeds  very  largely  upon  grasshoppers  during  those  months  when 
these  insects  are  plentiful.  As  individuals  they  are  among  the  most 
effective  feathered  grasshopper  destroyers. 

While  blackbirds  are  not  so  effective  as  individuals,  their  great 
numbers  make  them  of  even  greater  value  than  the  burrowing-owls. 

The  red-headed  woodpecker  is  quite  generally  condemned  for  peck- 
ing holes  in  buildings,  eating  fruit  and  occasionally  damaging  other  crops. 
Despite  his  bad  habits,  this  bird  is  not  without  good  points.  Over 
seventy  different  kinds  of  insects  enter  into  this  bird's  bill-of-fare,  which 
includes  many  crop  pests,  among  them  large  numbers  of  grasshoppers. 

Together  with  the  owls,  hawks  enjoy  a  bad  reputation  among  rural 
communities.  It  has  been  stated  that  of  over  seventy  species  of  hawks 

108 


Fig.   18.     The  Hair  Worm  shown  in  Figure   17, 
after  it  had  escaped  from  the  Beetle 


Grasshoppers 


Field  Crickets 


and  owls  found  in  the  United  States  but  six  are  considered  really  injurious. 
These  are  the  gyrfalcon,  duck  hawk,  sharp-shinned  hawk,  Cooper's  hawk, 
goshawk  and  great  horned  owl. 

The  little  sparrow  hawk  and  the  large,  dark  brown  Swainson's  hawk 
are  noted  insect  eaters.     Both  of  these  feed  freely  upon  grasshoppers. 


Fungous  Diseases 

During  late  sum- 
mer numbers  of 
dead  grasshoppers 
are  always  observed 
clinging  to  weeds 
and  other  plants 
along  the  roadside 
or  field  border. 
These  have  been 
killed  by  a  fungous 
disease  (Empusa 
gryWiFres.).  Grass- 
hoppers attacked 
by  this  disease 
climb  to  the  top  of 
some  plant  when 
about  to  die  and 
clasp  it  with  their 
fore  legs.  (Fig.  19, 
Page  109).  In  this 
position  they  die 
and  remain  clinging 
until  their  bodies 
become  so  decom- 
posed that  they 
fall  to  the  ground. 
This  seems  to  be 
the  most  common 
disease  attacking 
grasshoppers. 
However,  there  are 
several  other  fun- 
gous as  well  as  bacterial  diseases  which  destroy  some  grasshoppers 
nearly  every  year. 

4.     FIELD  CRICKETS 

(Fig.  7,  Plate  IV,  Page  17) 

Crickets  are  familiar  objects  during  late  summer  and  early  fall. 
Their  lively  chirping  during  mild  fall  evenings  seems  to  add  to  the  general 
spirit  of  harvest  cheer.  Yet  these  dusky  cousins  of  the  grasshopper  are 
not  without  their  bad  habits.  In  fact,  they  are  noted  for  their  appetites 
and  their  liking  for  such  articles  as  binder  twine,  clothes,  carpets  and 

109 


Fig.    19.     Grasshoppers   killed    by   the   Fungous    Disease, 
Empusa  grylli 


Field  Crickets 
Leaf -miners  Beei  or  Spinach  Leaf -miner 

rugs  Sugar  beets  are  also  sometimes  attacked.  The  leaf  stems  are 
often  eaten  and  deep  pits  are  eaten  in  the  crowns  of  the  beets.  Figure  7, 
Plate  IV,  Page  17  represents  an  immature  female  field  cricket. 

5.     LEAF-MINERS 

Thus  far  in  our  discussion  of  leaf  feeding  insects  only  those  which 
feed  exposed  on  the  surface  of  the  leaves  have  been  considered.  There  is 
another  group  of  leaf  feeders,  however,  which  live  protected  within  gal- 
leries, or  "mines,"  as  they  are  popularly  called,  which  result  from  the 
eating  away  of  the  pulp  of  the  leaves  while  the  outer  portion  or  epidermis 
is  left  untouched.  Some  of  these  mines  are  serpentine  in  form,  while 
others  are  irregular  in  shape,  becoming  unsightly  and  discolored  as  the 
season  advances. 

Several  species  of  leaf-miners  are  known  to  attack  sugar  and  garden 
beets  and  mangels.  However,  only  the  following  species  appears  to  do 
any  considerable  damage  to  the  sugar  beet  crop. 

(a)     BEET  OR  SPINACH  LEAF-MINER 

(Figs.  1,  2,  3.  4  and  5,  Plate  III,  Page  15) 
NATURE  OF  INJURY 

The  beet  leaf-miners  burrow  into  leaves  and  feed  upon  the  pulp. 
At  first  the  mines  appear  as  tortuous  whitish  or  brownish  lines  on  the 
blade  of  the  leaf.  As  the  miners  increase  in  size  the  mines  become  la.^ge, 
irregular  areas,  as  shown  in  Figure  1,  Plate  III,  Page  15. 

While  still  inhabited  the  mines  may  have  a  watery  appearance, 
and  in  case  the  greater  part  of  a  small  leaf  is  mined  out  the  leaf  droops 
and  appears  to  be  decaying.  If  such  leaves  are  held  between  the  ob- 
server and  a  strong  light  the  miner  can  be  seen  within,  usually  near  the 
side  of  the  mine.  . 

If  the  weather  is  very  warm,  dry  beet  leaves  may  wilt  and  lie  on  the 
hot  soil  during  very  warm  days'".  Sometimes  portions  of  these  leaves  are 
killed  by  the  heat.  These  dead  areas  often  appear  very  similar  to  the 
deserted  mines  of  leaf-miners.  They  can  be  distinguished  from  them 
very  easily,  however,  by  the  fact  that  the  pulp  still  remains,  there  being 
no  cavity  between  the  upper  and  lower  surfaces  of  the  leaves. 

Ordinarily  the  damage  to  sugar  beets  is  so  slight  that  no  account 
need  be  made  of  it.  Occasionally,  however,  the  miners  are  so  numerous 
that  they  materially  injure  a  crop.  The  destruction  of  the  inner  portion 
of  the  leaves  has  the  same  effect  as  though  the  entire  leaf  were  destroyed. 

METHODS  OF  CONTROL 

It  is  doubly  fortunate  that  the  injury  is  usually  so  slight  that  reme- 
dial measures  are  not  required,  as  there  is  no  known  remedy  practical 
for  field  use.  Several  poisons  have  been  tried,  but  all  have  proved  un- 
satisfactory. 

Picking  Infested  Leaves 

In  the  case  of  small  gardens  the  infested  leaves  can  be  picked  off 
and  destroyed.  This  will  prevent  the  rapid  multiplication  of  the  miners. 

no 


Beet  or  Spinach  Leaf -miner  Aphids  or  Plant-lice 

Clean  Culture 

As  in  the  case  of  many  other  insect  pests,  preventive  measures  are 
of  more  value  than  curative  ones.  The  beet  leaf-miner  feeds  in  the  leaves 
of  lamb's-quarters,  or  white  pigweed,  as  it  is  sometimes  called.  The 
destruction  of  this  weed  will  do  much  to  reduce  the  number  of  miners 
in  a  vicinity. 

DESCRIPTION  AND  LIFE  HISTORY 
The  Egg 

The  eggs,  which  are  placed  on  the  under  side  of  the  leaves  of  the 
host  plants,  are  shown  natural  size  in  Figure  1  "A,"  Plate  III,  Page  15. 
Usually  they  are  laid  side  by  side  in  groups  of  from  two  to  five  or  six. 
Their  surfaces  are  finely  reticulated.  Figure  2,  Plate  III,  Page  15  repre- 
sents three  eggs  much  enlarged,  showing  this  reticulation  of  the  surface. 

The  Miner 

The  miner  (Fig.  3,  Plate  III,  Page  15)  hatches  in  about  four  days. 
It  is  a  whitish  maggot,  pointed  at  the  head  and  broadening  toward  the 
opposite  end.  When  fully  grown  it  is  about  one-fourth  of  an  inch  long. 
As  soon  as  hatched  it  burrows  into  a  leaf  and  begins  to  feed  upon  the 
pulp. 

The  Pupa 

At  the  end  of  seven  or  eight  days  the  fully  grown  miners  drop  to  the 
ground  and  after  burying  themselves  just  below  the  surface  or  beneath 
trash  lying  on  it,  they  pass  into  the  pupal  stage  within  the  puparium 
(Fig.  4,  Plate  III,  Page  15).  The  pupal  state  lasts  from  ten  to  twenty 
days  during  warm  seasons  of  the  year.  The  last  generation  of  miners  in 
the  fall  is  thought  to  pass  the  winter  in  the  pupal  stage,  the  flies  emerging 
the  next  spring. 

The  Adult 

The  adult  miner  (Fig.  5,  Plate  III,  Page  15)  is  a  two-winged  fly 
belonging  to  the  same  order  as  the  common  house  fly.  This  fly  has  no 
very  distinctive  markings.  The  face  is  silvery  white  between  the  eyes, 
which  are  brownish.  The  body,  which  is  dull  grey,  is  sparsely  covered 
with  quite  long  stiff  hairs. 

B.     SUCKING  LEAF  FEEDERS 

(Aphids  or  Plant-lice,  True  Bugs,  Leaf-hoppers) 
1.     APHIDS  OR  PLANT-LICE 

Aphids,  or  plant-lice,  as  they  are  commonly  called,  are  small,  soft- 
bodied  creatures  which  usually  feed  in  compact  masses  on  the  stems, 
leaves  or  roots  of  plants.  Some  feed  exposed  upon  the  plant  (Fig.  20, 
Page  112),  others  cause  the  leaves  upon  which  they  feed  to  curl  over  them 
(Fig.  21,  Page  112),  and  still  others,  like  the  sugar  beet  root-louse,  spend 
a  part  of  the  season,  at  least,  within  galls  produced  by  their  feeding  upon 
the  host  plant  (Fig.  22,  Page  113). 

Ill 


Aphids  or  Plant-lice 


Fig.  20.     An  exposed  Colony  of  Plant-lice  on  a  common  roadside  Weed 


r.   21.     Leaves  of  White  Ash  curled  by  a  Plant-louse 
112 


Aphids  or  Plant-lice 


. 


Fig.  22.     Gall  of  Sugar  Beet  Root-louse  on  Leaves  of  Narrow-leaf  Cottonwood 


Fig.  23.     A  common  Wingless  Aphid;   Honey  Tubes  at  "A" 
\\3 


Aphids  or  Plant-lice 

NATURE  OF  INJURY 

The  indications  of  aphid  infestation  are  varied,  the  different  plant- 
lice  affecting  their  hosts  differently.  A  slow  growth  associated  with 
wilting  of  the  leaves,  which  are  apt  to  be  a  pale  yellowish  green,  is  char- 
acteristic of  root-louse  attack. 

Most  lice  which  feed  above  ground  prefer  the  new,  soft  growth  of 
plants.  If  the  leaves  and  new  growth  wilt,  if  the  leaves  are  covered  with 
a  sticky,  sweetish  substance  called  "honey  dew,"  or  if  they  become  curled 
and  distorted,  plant-lice  are  very  likely  present. 

Ants  are  very  fond  of  honey  dew  and  in  order  to  secure  it  are  known 
to  care  for  aphids  and  their  eggs,  exhibiting  in  this  an  instinct  which 
amounts  almost  to  reasoning.  Ants  and  aphids  are  so  closely  associated 
that  the  presence  of  the  former  on  a  plant  is  a  very  good  indication  that 
the  latter  are  present  also. 

METHODS  OF  CONTROL 

The  stomach  poisons  used  in  the  control  of  biting  insects 
will  not  kill  plant-lice.  Contact  poisons  must  be  used.  Even 
then,  the  control  of  those  aphids  which  live  within  galls  or  curled  leaves 
is  very  difficult  unless  the  remedy  is  applied  during  the  season  when  the 
lice  are  in  the  egg  stage  or  just  as  the  eggs  begin  to  hatch  in  the  spring. 
After  these  lice  once  become  inclosed  within  the  galls  or  leaves  it  is  impos- 
sible to  reach  them  with  any  contact  spray.  Several  species  are  so  cov- 
ered with  a  flocculent  secretion  that  a  spray  must  be  very  thoroughly 
applied  and  with  considerable  force  to  be  effective. 

Kerosene  Emulsion 

Where  only  a  few  plants  in  the  garden  or  a  small  number  of  orna- 
mental shrubs  are  to  be  treated,  kerosene  emulsion  has  long  been  a  stand- 
ard remedy  because  of  its  simplicity  and  the  fact  that  all  the  ingredients 
required  in  its  making  are  always  at  hand. 

This  contact  poison  is  usually  made  in  the  form  of  a  stock  solution, 
in  which  form  it  can  be  kept  for  several  weeks.  When  used  it  is  diluted 
by  adding  water.  The  s,tock  solution  is  made  as  follows: 

Mix  one-half  pound  of  common  laundry  soap  or  whale  oil  soap  in 
one  gallon  of  water  by  boiling  over  a  slow  fire  until  the  soap  is  completely 
dissolved.  After  removing  from  the  fire  add  two  gallons  of  kerosene  and 
beat  until  the  oil  is  thoroughly  mixed  with  the  soap  and  water. 

This  stock  solution  is  too  strong  for  any  plant  and  will  kill  the  leaves 
and  tender  parts  if  applied  to  them.  Before  using  thoroughly  mix  one 
part  of  the  stock  solution  with  ten  to  fifteen  parts  of  water.  Apply  a 
little  to  the  plants  to  be  treated  and  watch  the  results.  If  the  leaves 
are  burned  dilute  the  solution  still  more. 

Black  Leaf  40 

This  js  a  tobacco  preparation  containing  40  per  cent  nicotine,  or  the 
active  poison  in  tobacco.  As  a  remedy  for  plant-lice  one  part  of  "black 
leaf  40"  is  mixed  with  600  to  800  parts  of  water  and  sprayed  on  the  in- 
fested plants,  care  being  taken  to  spray  the  aphids  thoroughly.  As  the 
black  leaf  is  very  poisonous  great  care  should  be  taken  in  handling  it. 

114 


Aphids  or  Plant-lice 

Lime-sulphur  Mixture 

In  the  case  of  those  aphids  which  cause  the  leaves  to  curl,  spraying  in 
winter  or  early  spring  to  kill  the  eggs  and  newly  hatched  lice  is  most 
effective.  For  this  purpose  the  lime-sulphur  mixture  has  proved  satis- 
factory. This  mixture  may  be  made  on  the  farm,  but  it  can  be  pur- 
chased in  a  concentrated  form  from  insecticide  dealers  at  a  cost  not 
exceeding  that  of  making  it.  The  trees  or  shrubs  to  be  treated  should 
be  thoroughly  sprayed  before  the  buds  begin  to  open. 

Tobacco  Decoction 

This  is  made  by  boiling  tobacco  stems  or  powder  in  water.  Two 
pounds  of  the  former  to  four  gallons  of  the  latter  make  a  mixture  suffi- 
ciently strong  for  general  use.  Do  not  let  the  mixture  boil  violently  as 
this  drives  off  some  of  the  nicotine,  thus  reducing  its  strength. 

DESCRIPTION  AND  LIFE  HISTORY 

In  size  and  color  the  plant-lice  vary  greatly.  Among  the  larger 
species  the  bright  red  Macrosiphum  so  common  on  the  stems  of  golden- 
glow  in  late  summer  is  very  conspicuous.  Contrasted  with  this  is  the 
small  green  species  commonly  found  on  the  under  side  of  rose  leaves  and 
clustered  about  the  unopened  buds. 

Many  aphids  have  two  tubes  near  the  tip  of  the  abdomen  (Fig.  23, 
Page  113).  These  are  called  honey  tubes,  and  it  was  originally  supposed 
that  the  sweetish  liquid  or  honey  dew  which  is  discharged  from  the  ali- 
mentary canal  was  discharged  through  them. 

The  mode  of  reproduction  of  plant-lice  differs  from  that  of  other 
insects.  The  louse  hatching  from  the  over-winter  egg  and  all  of  the 
individuals  of  several  subsequent  generations  produce  living  young  with- 
out the  aid  of  the  male  element.  This  "asexual"  reproduction,  as  it  is 
called,  usually  continues  until  cold  weather  approaches.  In  the  fall 
true  males  and  females  are  produced.  These  mate  and  the  females 
produce  the  eggs  which  carry  the  species  over  winter. 

In  some  species  the  young  of  a  single  individual  consist  of  both  males 
and  females,  while  in  the  case  of  others  one  set  of  females  bear  all  female 
and  another  all  male  young. 

The  rate  of  reproduction  is  exceedingly  rapid,  a  generation  being 
produced  every  few  days  during  warm  weather.  This  rapid  multiplica- 
tion results  in  widespread  damage,  many  times,  before  the  presence  of 
the  lice  becomes  known. 

NATURAL  ENEMIES 

Were  it  not  for  the  natural  enemies  of  plant-lice  in  the  form  of  pre- 
dacious and  parasitic  insects,  fields,  orchards  and  gardens  would  soon  be 
overrun  by  them. 

Chief  among  these  natural  enemies  are  the  lady-beetles,  two  of  which 
are  shown  in  Figure  10,  Plate  II,  Page  13,  and  Figure  15,  Plate  IX,  Page 
27,  and  their  larvae  in  Figure  15,  Plate  II,  Page  13,  and  Figure  23,  Plate 
IX,  Page  27. 

115 


Aphid*  or  Plant-lice  Green  Peach-aphis 

The  aphis-lion  (Fig.  18,  Plate  IX)  and  its  parent  (Fig.  19,  Plate  IX), 
the  lace-winged  fly,   are  persistent  aphid  destroyers.     (See  pages  1 
and    134.) 

The  larvae  of  many  Syrphus-flies,  one  of  which  is  shown  in  Figure  13, 
Plate  VI,  Page  21,  devour  large  numbers  of  plant-lice. 

(a)     GREEN  PEACH-APHIS 

(Figs.  2,  9  and  10,  Plate  VIII,  Page  25)    , 

As  a  sugar  beet  pest  the  green  peach-aphis  is  of  little  importance. 
However,  under  favorable  conditions  for  its  multiplication,  it  often 
occurs  inconsiderable  numbers  on  the  under  side  of  beet  leaves. 

NATURE  OF  INJURY 

Injury  to  sugar  beets  is  due  to  the  withdrawing  of  the  sap  from  the 
leaves  by  the  aphids  in  feeding.  This  retards  the  growth  of  the  plants. 
The  presence  of  lice  is  sometimes  indicated  by  pale  green  or  whitish 
blotches  on  the  upper  side  of  the  leaves. 

As  its  name  indicates,  the  green  peach-aphis  is  found  on  the  peach 
tree.  It  also  feeds  upon  the  plum  tree.  Its  greatest  damage  is  done  to 
these  trees  during  early  summer. 

METHODS  OF  CONTROL 

Spray  infested  peach  and  plum  trees  with  lime-sulphur  mixture 
(See  page  115)  before  the  buds  open  in  the  spring  to  kill  eggs  and  newly 
hatched  stem-mothers.  After  the  buds  open  use  black  leaf  40.  (See 
page  114). 

The  lice  should  be  killed  on  the  fruit  trees.  After  they  have  mi- 
grated to  the  beets  it  is  practically  impossible  to  kill  them. 

DESCRIPTION 

The  apterous  or  wingless  lice  (Fig.  9,  Plate  VIII,  Page  25)  are  most 
plentiful.  A  few  winged  lice  (Fig.  10,  Plate  VIII,  Page  25)  may  be  found 
among  the  wingless  ones,  especially  during  the  latter  part  of  the  sum- 
mer. These  differ  from  the  wingless  individuals  in  coloring  as  well  as 
form.  The  most  distinguishing  mark  is  the  dark  patch  on  the  abdomen. 

LIFE  HISTORY 

In  early  spring  the  eggs,  which  are  deposited  on  peach  or  plum 
trees,  hatch.  In  a  few  days  the  pinkish  stem-mother,  as  the  louse  from 
the  egg  is  called,  becomes  mature  and  begins  depositing  her  young  on  the 
leaves.  These  young  are  not  pink  like  their  mother,  but  green,  as  shown 
in  Figure  9,  Plate  VIII,  Page  25.  In  due  time  these  green  lice  begin 
giving  birth  to  young. 

The  lice  of  this  third  generation  very  largely  become  winged  (Fig.  10, 
Plate  VIII,  Page  25).  These  winged  lice  migrate  to  a  number  of  annual 
plants  where  the  summer  generations  are  produced.  The  list  of  about 
eighty  plants  upon  which  this  louse  spends  the  summer  includes  nearly 
every  vegetable  grown  in  the  garden. 

116 


Green  Peach-aphis  Black  Beet-seed  Louse 

With  the  approach  of  fall  the  winged  lice  of  the  late  summer  gen- 
erations return  to  the  peach  and  plum  trees.  The  first  lice  to  return  to 
these  trees  give  birth  to  wingless  females  which  lay  eggs  instead  of  giving 
birth  to  young.  About  the  time  these  females  are  mature  the  winged 
males  begin  to  arrive  from  the  summer  hosts. 

After  mating  the  females  deposit  several  greenish  eggs,  which  later 
become  shining  black.  These  eggs  (Fig.  2,  Plate  VIII,  Page  25)  serve 
to  carry  the  species  through  the  winter. 

(b)  BLACK  BEET-SEED  LOUSE* 

(Figs.  6  and  7,  Plate  III,  Page  15) 

The  black  beet-seed  louse  is  notorious  because  of  its  injury  to  sugar 
beet  seed,  both  in  Europe  and  America.  In  this  country  it  has  been  par- 
ticularly destructive  in  some  of  the  western  states  where  beet  seed  is  being 
grown  on  a  commercial  scale. 

NATURE  OF  INJURY 

In  feeding  upon  beet  seed  plants  the  lice  congregate  in  compact  masses 
at  the  tip  of  the  growing  seed  branches.  Their  feeding  so  exhausts  the 
sap  that  the  plants  make  very  slow  growth  and  in  severe  cases  the  infested 
branches  die.  The  yield  of  seed  is  very  materially  reduced  as  a  result  of 
attack  by  this  louse. 

METHODS  OF  CONTROL 
Hand  Picking 

In  Europe  all  infested  branches  are  collected  and  carried  from  the 
field,  together  with  the  lice,  and  destroyed.  This  method  is  hardly  prac- 
ticable except  in  the  case  of  cheap  labor  and  selected  breeding  plants. 

Black  Leaf  40 

Spraying  infested  p'ants  with  black  leaf  40  (See  page  114),  one  part 
to  600  to  800  parts  of  water,  will  destroy  the  lice  and  not  affect  the  quality 
of  the  seed. 

Winter  Spraying 

Spraying  the  winter  host  with  lime-sulphur  mixture  (See  page  115) 
to  destroy  the  eggs  before  the  buds  open  or  with  black  leaf  40  (See  page 
114)  as  the  lice  are  hatching  in  spring  is  undoubtedly  the  most  effective 
means  of  controlling  this  pest. 

Destruction  of  Summer  Hosts 

When  lice  occur  on  wild  plants  during  the  summer  these  should  be 
destroyed,  together  with  the  lice  on  them.  The  destruction  of  all  wild 
host  plants  in  the  vicinity  of  beet  seed  fields,  before  they  become  infested, 
is  to  be  recommended. 


*There  is  some  evidence  that  there  may  be  more  than  one  species  of  black  louse  attacking  beet 
seed  in  the  United  States.  This  Bulletin  discusses  but  one,  the  species  damaging  beet  seed  in  Northern 
Colorado. 

117 


Black  Beet-seed  Louse 


DESCRIPTION 

The  black  beet-seed  louse  occurs  in  three  forms. 


1.  Wingless  Lice 

The  majority  of  the 
lice  during  the  warmer 
months  are  wingless. 
These  wingless  lice  (Fig. 
6,  Plate  III,  Page  15) 
are  a  very  dark,  dull 
green.  As  the  name 
implies,  they  are  so 
dark  as  to  appear  black, 
with  the  exception  of 
the  legs,  which  are 
yellowish.  Some  of  the 
older  individuals  have 
several  white  tufts  on 
the  abdomen. 

2.  Pupae 

As  the  season  ad- 
vances many  of  the  lice 
develop  wing  pads. 
These  are  the  imma- 
ture "alate"  or  winged 
lice.  These  pupae,  as 
they  are  sometimes 
called,  also  have  the 
white  tufts  on  the  ab- 
domen. 

3.     Winged  Lice 

The  color  of  the 
winged  lice  (Fig.  7, 
Plate  III,  Page  15)  is 
similar  to  that  of  the 
wingless  individuals 
except  that  the  head 
and  thorax  (that  part 
of  the  body  just  back  of  the  head)  are  a  shining  black.  The  wings  show 
rainbow  colors  when  the  light  strikes  them  at  the  proper  angle. 

LIFE  HISTORY 

The  life  history  of  this  louse  is  very  similar  to  that  of  the  green  peach- 
aphis. 

The  winter  is  spent  in  the  egg  stage  on  the  twigs  of  a  shrub  variously 
known  in  different  parts  of  the  country  as  spindle  tree,  burning  bush, 
waahoo,  and  strawberry  bush  (Fig.  24,  Page  1 18). 

The  first  winged  lice  in  the  summer  migrate  to  the  summer  hosts, 
which  include  beet  seed  and  a  variety  of  weeds  and  wild  plants,  poppies, 

118 


Fig.  24.     A  Branch  of  Euonymus  Species,  showing 
Star-shaped  Fruit 


Black  Beet-seed  Louse 
True  Bugs  False  Chinch  Bug 

and  several  varieties  of  beans,  especially  the  horse  bean  of  Europe.  In 
the  fall  the  migrants  return  to  the  winter  host,  where  the  sexual  forms 
mate  and  the  eggs  are  produced. 

2.     THE  TRUE  BUGS 

People  who  are  not  familiar  with  their  classifications  are  apt  to  apply 
the  word  "bug"  to  all  insects.  However,  strictly  speaking,  this  name 
is  only  properly  applied  to  those  sucking  insects  belonging  to  the  order 
Hemiptera.  Many  authors  confine  the  term  to  individuals  of  the 
sub-order  Heteroptera.  Like  most  of  the  scientific  names  of  insects, 
this  one  seems  unnecessarily  long  and  meaningless  to  the  average  reader. 
It  is  taken  from  two  Greek  words,  "heteros,"  meaning  diverse,  and 
"petron,"  a  wing,  and  was  suggested  by  the  peculiar  form  of  the  wing  of 
these  bugs. 

The  common  stink-bug  so  frequently  encountered  on  raspberries 
and  other  small  fruits  and  the  notorious  chinch  bug  of  the  grain  fields  of 
the  Mississippi  Valley  are  familiar  representatives  of  this  group. 

Several  species  attack  the  sugar  beet,  of  which  the  false  chinch  bug 
is  the  most  important  in  the  arid  West. 

(a)     FALSE  CHINCH  BUG 

(Figs.  11  and  12,  Plate  VIII,  Page  25) 

This  insect  has  attracted  quite  widespread  attention  because  of  its 
damage  to  sugar  beet  seed.  When  very  numerous  it  has  been  known 
seriously  to  injure  commercial  sugar  beets  also. 

NATURE  OF  INJURY 

In  feeding,  the  false  chinch  bug  congregates  in  compact  masses  upon 
a  few  plants.  The  juice  of  these  plants  is  so  rapidly  exhausted  that  they 
wilt  and  become  lifeless  in  a  very  short  time. 

When  attacking  commercial  beets  the  bugs  congregate  about  the 
crowns  of  small  plants,  or  on  the  leaves,  which  soon  become  wilted  and 
dead.  The  growth  of  commercial  beets  is  very  much  retarded  and  in 
extreme  cases  small  beets  are  killed. 

The  growing  tips  of  the  branches  of  seed  beets  are  attacked.  The 
sap  of  these  is  soon  so  exhausted  that  they  droop  and  die.  The  yield  of 
seed  is  very  much  reduced  by  the  feeding  of  this  pest. 

When  the  sap  of  one  plant  is  exhausted  the  bugs  move  to  others, 
and  as  they  are  strong  fliers  and  voracious  feeders  they  affect  large  areas 
in  a  short  time. 

Fields  of  commercial  beets  near  waste  land  overgrown  with  pepper- 
grass  or  shepherd's  purse  and  other  plants  of  the  mustard  family  are 
quite  apt  to  be  attacked. 

The  odor  of  the  blossoms  of  seed  beets  seems  to  attract  the  false 
chinch  bug,  which  usually  appears  in  seed  fields  about  the  time  the  plants 
begin  to  bloom.  Of  course  the  proximity  of  infested  land  to  seed  fields 
increases  the  infestation,  at  least  early  in  the  season. 

119 


False  Chinch  Bug 

METHODS  OF  CONTROL 
Clean  Culture 

In  the  control  of  the  false  chinch  bug  preventive  measures  give  more 
satisfactory  results  than  the  application  of  any  remedy  yet  devised.  As 
has  already  been  intimated,  this  insect  breeds  upon  various  wild  plants, 
especially  shepherd 's-purse  and  other  closely  related  plants  of  the  mus- 
tard family.  By  preventing  these  weeds  from  growing  about  fields, 
ditch  banks  and  roadsides  the  multiplication  of  the  false  chinch  bug  in 
a  vicinity  will  be  materially  checked. 

Burning 

The  bugs  probably  spend  the  winter  in  hibernation  beneath  dead 
weeds  and  about  the  roots  of  grasses  growing  on  waste  land.  If  all  un- 
plowed  land  is  cleaned  up  during  the  winter  and  early  spring  by  burning 
all  dead  vegetation  the  hibernating  bugs  will  be  destroyed.  If  straw 
is  spread  over  the  ground  and  burned  the  treatment  is  often  more  effec- 
tive. Many  other  injurious  insects  which  spend  the  winter  in  hiberna- 
tion in  the  same  locations  as  the  false  chinch  bug  will  be  destroyed  at 
the  same  time. 

Hand  Picking 

Hand  picking  under  certain  conditions  will  serve  to  prevent  the 
insect  from  injuring  a  crop.  In  catching  the  bugs  a  wide-mouthed  dish 
of  some  kind  should  be  used.  Place  a  small  quantity  of  water  in  this  to 
which  a  little  kerosene  has  been  added.  By  suddenly  slapping  the 
infested  plants  the  bugs  can  be  knocked  into  the  water  and  kerosene. 
The  latter  soon  kills  them.  When  the  dead  bugs  cover  the  surface  of 
the  liquid  skim  them  off.  Whether  or  not  this  method  of  control  is 
practicable  will  depend  upon  the  value  of  the  crop  and  the  labor  required. 
It  is  doubtful  if  it  will  pay  in  the  case  of  large  fields.  In  order  that  it  be 
most  effective  the  work  must  be  done  during  the  early  morning  or 
cool  days,  as  in  bright  sunny  weather  the  bugs  are  so  active  that  they 
scatter  upon  the  approach  of  the  worker,  so  that  but  a  small  proportion 
are  caught. 

Sticky  Shields 

Sticky  shields*  carried  through  the  fields  have  been  used  with  some 
success.  The  same  question  of  crop  and  labor  values  makes  this  a  doubt- 
ful method  except  for  small  plots  of  very  valuable  crops  and  crops  grown 
for  experimental  purposes. 

Spraying 

Various  sprays  have  been  employed,  with  rather  indifferent  results. 
Mr.  F.  B.  Milliken*  reports  the  killing  of  this  pest  by  spraying  with 
whale  oil  soap,  one  pound  of  soap  to  five  gallons  of  water.  According  to 

*F.  B  M  !  :ken,  "The  False  Chinch  Bug  and  Measures  for  Controlling  It."  Farmers'  Bulletin  No. 
762.  U.  S.  Department  of  Agriculture  (1916). 

120 


False  Chinch  Bug 

this  author  the  above  is  too  strong  for  turnips  and  radishes,  for  which 
one  pound  of  soap  to  ten  gallons  water  should  be  used,  adding  one  part 
of  nicotine  sulphate  to  1000  parts  of  water. 

DESCRIPTION 
The  Egg 

The  eggs,  which  are  deposited  in  crevices  of  the  ground  and  upon 
certain  plants,  are  very  small,  being  about  Jj  of  an  inch  long  by  about 
one-fourth  as  wide  at  the  greatest  diameter.  They  are  finely  ribbed 
lengthwise.  The  color  is  pale  yellowish  white,  taking  on  an  orange  tinge 
as  the  young  bug  develops  within. 

The  Nymph 

The  nymphs  are  slightly  reddish  when  first  hatched,  becoming  grayer 
with  age.  When  about  half  grown  they  appear  as  shown  in  Figure  11, 
Plate  VIII,  Page  2 5. 

The  Adult 

The  adult  (Fig.  12,  Plate  VIII,  Page  25)  is  about  &  of  an  inch  long. 
The  color  of  the  head,  body  and  legs  is  brownish  gray,  with  fine  dark 
spots  over  the  surface.  These  spots  are  especially  prominent  on  the  legs. 
The  wings  are  whitish.  The  color  of  the  body  showing  through  them 
gives  them  a  grayish  appearance. 

LIFE  HISTORY 

The  number  of  broods  produced  annually  will  depend  upon  the 
latitude  and  general  weather  conditions  prevailing.  There  are  probably 
four  or  five  in  the  latitude  of  Denver. 

According  to  the  author  already  quoted,*  the  late  fall  and  early 
spring  broods  deposit  their  eggs  in  cracks  in  the  soil  surface  or  in  pul- 
verized soil.  During  the  warmer  months  the  eggs  are  thrust  among 
the  clustered  parts  of  plants  such  as  the  flower  heads  of  some  weeds** 
and  the  glumes  of  the  strong  scented  stink-grass  or  love-grass. 

When  first  hatched  the  young  feed  upon  weeds  almost  exclusively, 
especially  the  shepherd's-purse,  peppergrass  and  pennycress. 

At  maturity  the  adults  scatter  to  other  plants.  It  is  at  this  time 
that  beet  seed  fields  become  infested. 

The  adults  of  the  last  generation  in  the  fall  spend  the  winter  in 
hibernation. 

NATURAL  ENEMIES 

Very  little  seems  to  be  known  of  the  natural  enemies  of  this  bug. 
The  writer  has  observed  many  adults  containing  the  maggots  of  a  small 
two- winged  fly. 

Many  bugs  were  killed  by  a  fungous  disease  in  breeding  cages,  but 
no  noticeable  effect  of  this  malady  was  observed  in  the  field. 

*F.  B.  Milhken.  "The  False  Chinch  Bug  and  Measures  for  Controlling  It."  Farmers'  Bu'ietin  No. 
762.  U.  S.  Department  of  Agriculture  (1916). 

**Caillardia  pulchella  Foug.     Mollugo  verticillata  L. 

121 


Tarnished  Plant-bug 
(b)     TARNISHED  PLANT-BUG 

The  tarnished  plant-bug  is  one  of  the  most  common  of  the  true 
bugs.  It  is  found  everywhere  in  North  America  from  Mexico  to  Canada 
and  feeds  upon  almost  any  plant,  either  cultivated  or  wild.  This  bug 
often  attacks  sugar  beets. 

NATURE  OF  INJURY 

Only  when  tarnished  plant  bugs  are  abundant  are  there  any  visible 
effects  of  their  feeding.  During  the  latter  part  of  the  season,  however, 
they  often  attack  the  young  leaves  at  the  center  of  the  beet  crown  in 
such  numbers  that  the  tips  of  these  leaves  wilt  and  finally  become  brown 
and  dry.  Frequently  the  injured  beets  begin  to  make  growth  in  the 
axil  of  the  outer  leaves.  This  gives  the  beet  top  a  bushy  appearance. 

METHODS  OF  CONTROL 

Sugar  beets  are  rarely  injured  to  the  extent  where  remedial  measures 
are  profitably  applied. 

Clean  Culture 

Since  the  tarnished  plant-bug  spends  the  winter  in  hibernation 
under  the  trash  about  fields,  ditch  banks  and  fence  rows  and  breeds  on 
the  weeds  growing  in  these  places  during  the  early  part  of  the  season, 
cleaning  up  all  waste  land  by  burning  during  winter  or  early  spring  will 
destroy  many  of  them.  By  preventing  the  weeds  from  growing  about 
fields  the  bugs  are  not  so  apt  to  be  attracted  to  them  as  when  these  wild 
plants  are  plentiful  in  and  about  them. 

Kerosene  Emulsion 

In  the  case  of  small  garden  plots  kerosene  emulsion  (Page  1 14)  is 
probably  the  best  remedy  where  the  nature  of  the  crop  attacked  is  such 
that  it  can  be  used. 

Dr.  F.  H.  Chittenden*  states  that  where  insecticides  are  used  they 
should  be  applied  early  in  the  morning  while  the  dew  is  still  on  the  plants 
anjd  the  bugs  are  not  very  active. 

Hand  Picking 

Hand  picking  may  be  resorted  to  where  the  areas  covered  by  the 
attack  are  small.  It  is  obvious  that  this  method  is  not  suited  to  large 
fields. 

DESCRIPTION 
The  Egg 

The  eggs,  which  are  about  ^  of  an  inch  long,  are  oval,  several  times 
as  long  as  thick  and  flared  at  one  end  so  as  to  be  somewhat  bottle-shaped. 
The  color  is  a  pale  yellow. 

The  Nymph 

The  nymphs  pass  through  four  stages  in  the  course  of  their  devel- 
opment. In  the  first  stage  they  are  about  ^  of  an  inch  in  length  and 
of  a  yellowish  or  yellowish  green  color. 

~f  tr     *"A.Brief.  Account  of  the  Principal  Insect  Enemies  of  the  Sugar  Beet."  Bulletin  No.  43.  Division 
of  Entomology.  U.  b.  Department  of  Agriculture  (1903). 

122 


Tarnished  Plant-bug 
Leaf-hoppers  Sugar  Beet  Leaf -hopper 

The  second  stage  differs  from  the  first  in  that  the  nymphs  are  about 
twice  as  large  and  have  two  pairs  of  dark  spots  on  the  thorax. 

These  spots  become  more  distinct  in  the  third  stage  and  the  wings 
are  represented  by  two  small  pads  on  the  back  margin  of  the  thorax. 

In  the  fourth  stage  the  wing  pads  reach  nearly  half  way  down  the 
back  and  the  four  dark  spots  become  quite  prominent. 

The  Adult 

The  adults  are  nearly  one  quarter  of  an  inch  in  length.  The  color 
ranges  from  a  greenish  to  a  brassy  brown.  The  markings  are  quite 
variable.  Some  individuals  are  quite  prominently  marked  with  black, 
yellow  and  red,  while  others  are  much  more  modestly  colored,  greenish 
brown  predominating. 

LIFE  HISTORY 

The  adults,  as  already  mentioned,  as  well  as  some  nymphs  in  the 
third  and  fourth  stages,  hibernate  under  any  convenient  trash  or  under 
stones,  boards  and  leaves  about  fields  and  waste  land. 

The  adults  emerge  during  the  first  warm  days  of  spring,  and  egg- 
laying  begins  soon  after  emergence.  Little  seems  to  be  known  about 
the  place  where  the  eggs  are  deposited.  In  all  probability,  they  are 
placed  within  the  stems  of  the  plants  upon  which  the  adults  feed.  In 
the  latitude  of  Northern  Colorado  the  eggs  of  the  first  generation  are 
deposited  about  the  last  of  April  and  early  May. 

About  a  month  is  required  for  the  development  of  a  single  generation. 
Therefore,  there  are  probably  two  or  three  generations  each  season. 

The  generations  overlap  to  such  an  extent  that  nymphs  of  all  stages 
and  adults  can  be  found  feeding  together  during  the  entire  summer. 

NATURAL  ENEMIES 

Very  little  is  known  regarding  the  natural  enemies  of  this  insect.  In 
all  probability  it  is  held  in  check  by  predacious  and  parasitic  insects 
and  fungous  diseases  similar  to  those  attacking  the  false  chinch  bug. 

3.     LEAF-HOPPERS 

With  the  exception  of  the  aphids,  leaf-hoppers  probably  exceed  in 
number  of  individuals  all  other  families  of  sucking  insects  attacking 
cultivated  crops. 

Although  most  leaf-hoppers  feed  upon  grasses,  often  occurring  in 
meadows  in  such  numbers  that  it  has  been  estimated  that  from  one- 
fourth  to  one-half  of  all  the  grass  growing  annually  is  destroyed  by  them, 
several  species  seriously  damage  field  crops,  vegetables,  fruits  and  shrubs. 

The  small  cream  colored  rose  leaf-hopper  which  causes  the  whitish 
blotches  on  the  leaves  of  cultivated  and  wild  roses  is  familiar  to  nearly 
every  one  and  will  serve  as  a  typical  example  of  this  group  of  insects, 
several  species  of  which  attack  the  sugar  beet. 

(a)     SUGAR  BEET  LEAF-HOPPER 

(Figs.  5,  6  and  7,  Plate  VIII,  Page  25) 

Few  insects  attacking  the  sugar  beet  cause  as  large  annual  losses  as 
this  minute  leaf-hopper.  Fortunately  this  pest  has  not  appeared  to  any 

123 


Sugar  Beet  Leaf-hopper 

damaging  extent  in  the  territory  in  which  The  Great  Western  Sugar 
Company  operates. 

Its  association  with  the  disease  known  as  curly-top,  (Fig.  5,  Plate 
VIII  Page  25),  or  more  locally  as  "blight,"  "western  blight"  or  "whis- 
kered beets"  (Fig.  7,  Page  60),  has  long  been  known,  but  just  how  its 
feeding  produces  the  malady  is  not  so  well  known. 


Fig.   25.     Sugar  Beet  showing  characteristic   Curling  rf  Leaves  caused  by  Curly-top 

1.   U.  S.   Bur 


(After  Harry  B.   Shaw,   Bulletin  No.   181. 


reau   of  Plant  Industry) 


NATURE  OF  INJURY 

Indications  of  Injury 

The  symptoms  of  injury  by  this  leaf-hopper  are  to  be  found  upon  all 
parts  of  the  plant.  The  first  to  appear  is  usually  an  inward  curling  of  the 
inner  leaves.  This  is  associated  with  a  distortion  and  enlargement  of  the 
veins  of  the  leaf  (Fig.  5,  Plate  VIII,  Page  25).  In  severe  cases  the  veins 
are  covered  with  nipple-like  protuberances.  As  the  disease  advances 
the  whole  plant  becomes  affected.  The  leaves  become  badly  crumpled 
(Fig.  25,  Page  124),  the  stunted  roots  develop  an  abnormally  large  num- 
ber of  fibrous  rootlets  from  the  root  seams  (Fig.  7,  Page  60),  and  the 
root  itself  becomes  darkened,  especially  where  the  rings  of  fibrovascular 
bundles  show  in  cross  sections  (Fig.  26,  Page  125).  The  crown  of  the 
beet  will  often  be  covered  with  a  sweet  gummy  substance  which  exudes 
from  the  beet. 

How  the  Disease  is  Transmitted 

In  some  way  not  at  present  thoroughly  understood,  certain  so  called 
virulent  leaf-hoppers  have  the  power  of  producing  curly-top  in  healthy 
beets.  A  single  individual  which  possesses  this  power  will  infect  a 
healthy  plant  if  confined  upon  it  for  five  minutes.* 

*E.  D.  Ball  •'The  Beet  Leafhopper  and  the  Curly-leaf  Disease  That  It  Transmits."  Bulletin  No.  155. 
Utah  Agricultural  College  (1917). 

124 


Sugar  Beet  Leaf-hopper 

Normal  individuals  do  not  have  the  power  to  cause  the  disease.  It 
has  been  demonstrated  quite  recently  that  before  a  sugar  beet  leaf-hopper 
can  transmit  curly-top  it  must  itself  become  inoculated  by  feeding  upon 
a  diseased  plant. 

There  seem  to  be  many  points  in  common  between  the  carrying  of 
curly-top  by  these  leaf-hoppers  and  the  relation  existing  between  certain 
mosquitoes  and  malaria  fever  transmission.  The  micro-organism  which 
is  now  supposed  to  be  the  real  cause  of  the  disease  must  be  taken  up  by 
the  leaf-hoppers  while  feeding  on  a  diseased  plant  and  then  transmitted 
to  healthy  plants  during  the  process  of  feeding  upon  them. 


' 


Fig.   26.      Cross  Section  of  Sugar  Beet,  showing  Darkening  of  Rings  caused  by  Cuily-top 
(After  C.  O.  Townsend,  Bulletin  No.  122,  U.  S.  Bureau  of  Plant  Industry) 

Investigations,  the  results  of  which  have  just  been  published,* 
emphasize  the  importance  of  clean  culture  as  a  possible  means  of  con- 
trolling this  insect. 

These  investigations  show  that  without  a  doubt  the  wild  host  plants 
of  the  beet  leaf-hopper  become  diseased  and  that  when  fed  upon  by  non- 
virulent  leaf-hoppers,  these  insects  become  inoculated  and  can  and  do 
transmit  the  disease  to  healthy  sugar  beets.  The  plant  experimented 
with  was  a  common  mallow. 

METHODS  OF  CONTROL 

There  is  very  little  to  be  said  regarding  the  control  of  this  insect. 
In  fact  there  is  no  known  method  by  which  curly-top  can  be  prevented. 

The  practicing  of  clean  culture  and  the  working  and  burning  over  of 
all  possible  hibernating  places  is  always  to  be  recommended,  but  even 
this  is  not  sufficient.  Until  more  is  known  of  the  insect  and  its  associa- 
tion with  curly-top  we  cannot  hope  to  be  able  satisfactorily  to  prevent 
the  damage  it  causes.  There  are  cases  on  record  where  early  planting 
prevented  injury.  This  does  not  seem  to  be  a  sure  remedy  in  all  locali- 
ties, however. 

*"  Wild  Vegetation  as  a  Source  of  Curly-top  Infections  of  Sugar  Beets."  Boniquit  and  Slake.  Journal 
of  Economic  Entomology.  Vol.  10.  No.  4  (1917). 

125 


Sugar  Beet  Leaf-hopper  Clover  Leaf-hopper 

DESCRIPTION 
The  Egg 

The  eggs,  which  are  pearly  white,  are  deposited  in  the  tender  stems 
of  beet  leaves.  Late  in  the  season  the  elliptical  scars  caused  by  the 
punctures  made  in  depositing  the  eggs  are  sometimes  very  numerous. 

The  Nymph 

The  young  leaf-hoppers  or  nymphs  (Fig.  6,-Plate  VIII,  Page  25)  are 
very  minute,  active  little  fellows  of  a  creamy  white  color.  They  are  so 
small  and  so  easily  disturbed  that  they  are  found  only  by  making  very 
careful  search  for  them. 

The  Adult 

The  fully  matured  sugar  beet  leaf-hopper  (Fig.  7,  Plate  VIII,  Page 
25)  is  about  one-eighth  of  an  inch  long,  and  with  the  exception  of  the  eyes, 
is  of  a  light  creamy  white  color.  They  are  so  exceedingly  small  and  active 
that  they  are  very  difficult  to  observe  in  the  field  except  as  they  fly  from 
plant  to  plant. 

LIFE  HISTORY 

The  following  summary  of  the  life  history  and  habits  is  taken  from 
U.  S.  Department  of  Agriculture  Bulletin  No.  181,  by  Harry  B.  Shaw: 

"The  beet  leaf-hopper  is  single  brooded  and  begins  to  deposit  its 
tiny,  white  eggs  in  the  stems  and  midribs  of  beet  leaves  from  about  the 
end  of  June — the  time  doubtless  varying  somewhat  with  the  locality  and 
local  climatic  conditions — until  the  end  of  August.  Probably  the  major- 
ity of  the  eggs  are  deposited  by  the  middle  of  July.  The  nymphs  begin 
to  appear  about  the  second  week  in  July,  and  the  writer  has  observed 
their  appearance  in  considerable  numbers  in  Idaho  as  late  as  the  end  of 
August.  Slit-like  scars  are  produced  on  the  beet  stems  where  the  eggs 
have  been  deposited;  sometimes  these  ovipository  scars  are  very  numer- 
ous and  conspicuous.  The  egg  stage  appears  to  last  about  fifteen  days, 
and  the  young  insects  reach  the  adult  stage  in  about  twenty  days  more. 
These  adults  hibernate  and  resume  their  activity  the  following  spring. 
In  Utah  and  Idaho  they  have  been  seen  on  weeds  in  May  and  on  beets 
near  the  end  of  May  or  early  in  June.  The  greater  portion  of  the  nymph 
stage  appears  to  be  spent  among  the  inner  leaves  and  petioles  of  the  plant, 
where  the  egg  is  hatched,  and  as  the  insect  approaches  the  adult  stage  it 
gradually  works  outward. 

"The  beet  leaf-hopper  is  an  exceedingly  active  insect;  its  favorite 
mode  of  locomotion  is  by  hops  of  lightning-like  rapidity.  The  range  of 
its  leaps  seems  to  be  about  18  inches.  The  adult  while  on  beets  uses  its 
wings  but  little.  In  common  with  several  closely  related  species  it  is  a 
true  sucking  insect;  it  is  provided  with  powerful  head  parts  and  a  stout 
bill.  The  latter  when  not  in  use  is  tucked  snugly  against  the  under  side 
of  the  body." 

(b)     CLOVER  LEAF-HOPPER 
(Fig.  8,  Plate  VI II,  Page  25) 

The  clover  leaf-hopper  is  frequently  encountered  in  quite  large  num- 
bers in  beet  fields  and  is  often  mistaken  for  the  sugar  beet  leaf-hopper 
just  discussed.  It  can  be  easily  distinguished  from  it,  however,  by  its 

126 


Clover  Leaf-hopper 

more  robust  form,  slightly  larger  size  and  darker  color.  The  two  dark 
spots  on  the  head  between  the  eyes  serve  to  distinguish  it  from  many 
other  small,  grayish  species  with  which  it  is  often  associated  in  clover 
and  alfalfa  fields,  where  its  greatest  damage  is  done. 

NATURE  OF  INJURY 

Fields  of  sugar  beets  where  this  crop  has  followed  alfalfa  have  been 
seriously  damaged  in  the  early  part  of  the  season  while  the  beets  were 
still  small.  The  injury  is  most  severe  during  dry,  hot  weather. 

The  leaves  of  sugar  beets  attacked  by  this  insect  are  covered  with 
light,  grayish  areas  as  a  result  of  the  punctures  and  irritation  caused  in 
feeding.  If  the  weather  is  dry  and  warm  the  plants  show  a  very  striking 
lack  of  thrift  and  make  very  slow  growth.  An  examination  of  such  beets 
will  reveal  the  leaf-hoppers  on  the  under  side  of  the  leaves,  or  during 
bright  sunny  days  they  will  be  seen  flying  ahead  of  one  walking  through 
the  field. 

METHODS  OF  CONTROL 
Clean  Culture 

Keeping  waste  land  free  of  rubbish  by  burning  all  dead  vegetation 
during  the  fall  will  prevent  the  adults  from  hibernating  about  fields. 
Burning  during  the  winter  or  early  spring  will  destroy  the  hibernating 
adults. 

DESCRIPTION 
The  Egg 

The  eggs,  which  are  white  and  very  small,  are  placed  in  slits  in  the 
host  plants.  These  slits  are  made  with  the  saw-like  ovipositor  of  the 
female. 

The  Nymph 

The  young  or  nymphs  resemble  the  adults  in  form  but  lack  the  wings 
of  the  latter.  Their  color  is  a  creamy  white  with  darker  spots  and  bands. 

The  Adult 

The  adult  leaf-hopper  (Fig.  8,  Plate  VIII,  Page  25)  is  of  a  light  gray- 
ish color  with  dark  markings.  The  face  is  marked  with  short,  dark 
stripes  and  just  between  the  eyes  on  the  top  of  the  head  are  two  dark 
spots. 

LIFE  HISTORY 

The  hibernating  female  places  her  eggs  in  the  stems  of  plants  in  early 
spring.  These  hatch  in  from  five  to  twelve  days  during  the  warmer 
months. 

The  number  of  generations  varies  with  the  latitude  and  general 
weather  conditions.  In  the  latitude  of  Denver  there  are  at  least  two 
and  probably  three  each  year. 

The  nymph  stage  lasts  from  20  to  30  days,  with  an  average  of  about 
25  days.  The  last  generation  hibernates  during  the  winter  at  the  base 
of  clumps  of  grass  and  about  the  roots  of  weeds  or  under  rubbish  lying 
about  fields  and  waste  lands. 

127 


Clover  Leaf-hopper  Eulettix  Strobi 

In  the  warmer  sections  of  the  Southern  states  the  adults  are  more  or 
less  active  during  the  entire  year,  and  in  the  extreme  South  they  do  not 
hibernate  at  all. 

(c)     EUTETTIX  STROBI  FITCH 
(Figs.  1,  3  and  4,  Plate  VIII,  Page  25) 

This  bright  colored  leaf-hopper  (Fig.  4,  Plate  VIII,  Page  25)  is  the 
cause  of  the  deep  purple  blotches  (Fig.  1,  Plate  VIII,  Page  25)  so  often 
seen  on  the  leaves  of  lamb's-quarters  and  sugar  beets  during  spring  and 
summer. 

It  is  not  of  interest  to  beet  growers  because  of  any  damage  it  does 
to  the  crop  but  because  of  the  widespread  attention  which  the  discolora- 
tion of  the  leaves,  caused  by  its  feeding,  attracts. 

During  late  spring  and  early  summer  and  again  during  late  summer 
the  nymphs  (Fig.  3,  Plate  VIII,  Page  25)  may  be  found  on  the  under 
side  of  the  leaves,  resting  on  the  colored  spots.  Their  color  harmonizes 
so  completely  with  these  spots  that  they  are  easily  overlooked. 

The  adults  (Fig.  4,  Plate  VIII,  Page  25)  are  very  prettily  marked 
with  shades  of  tan  and  brown,  and  measure  about  one-fourth  of  an  inch 
in  length.  The  dark  saddle  across  the  center  of  the  wings  is  especially 
prominent.  This  is  one  of  our  most  brightly  colored  and  attractive 
leaf-hoppers.  There  appear  to  be  two  broods  of  this  insect  annually, 
the  adults  appearing  in  June  and  August. 


128 


Beneficial  Insects 
CHAPTER  IV 


BENEFICIAL  INSECTS 

So  much  is  written  about  the  injurious  insects  in  bulletins  and  farm 
papers  that  we  are  apt  to  look  upon  all  insects  as  the  arch-enemies  of 
mankind.  However,  if  we  study  those  about  us  carefully  we  are  soon 
astonished  at  the  number  of  friends  we  have  among  them,  friends  whose 
whole  existence  is  one  constant  warfare  against  our  enemies.  It  is  not 
enough  that  we  learn  to  recognize  enemies  alone;  we  should  know  our 
friends  as  well  and  do  all  we  can  to  encourage  and  protect  them. 

In  the  preceding  pages  frequent  mention  has  been  made  of  beneficial 
insects  in  connection  with  the  particular  injurious  species  which  they 
help  to  control.  However,  out  of  justice  to  our  insect  friends  and  our- 
selves it  is  only  right  that  we  devote  a  few  pages  to  a  general  discussion 
of  this  large  but  little  appreciated  group. 

Every  order  of  insects  contains  forms  which  feed  upon  other  forms 
of  insect  life.  However,  these  friendly  species  are  in  some  cases  so 
minute  that  they  are  overlooked,  or  their  work  of  ridding  our  fields  of 
noxious  insects  is  carried  on  so  quietly  that  their  presence  is  not  apparent. 
Still  others  so  resemble  some  of  the  injurious  species  that  their  real  mis- 
sion is  not  suspected.  Instead  they  are  blamed  for  the  damage  they  are 
really  helping  to  prevent.  Many  times  friends  are  taken  for  foes  because 
in  searching  for  the  real  culprits  they  are  forced  to  frequent  the  damaged 
crop.  Unless  we  are  familiar  with  these  insects  they  often  share  the  fate 
of  the  spy  who,  in  order  to  hide  his  identity  more  completely,  appears  in 
the  role  of  an  enemy. 

Beneficial  insects  are  spoken  of  as  either  predacious  or  parasitic. 
Owing  to  the  fact  that,  in  habits,  these  two  groups  are  not  clearly  denned, 
but  merge  one  into  the  other,  it  is  very  difficult  to  give  a  definition  of 
the  terms  predacious  and  parasitic  which  is  wholly  satisfactory. 

In  a  general  way  insects  which  wander  about  in  search  of  the  insects 
upon  which  they  feed  are  spoken  of  as  being  predacious.  Insects  of  this 
class  require  many  hosts  or  victims  for  their  maintenance. 

Insects  which  pass  the  entire  larval  stage  within  the  body  of  a  single 
host,  or  attached  to  a  single  host  from  which  they  draw  their  nourish- 
ment, are  said  to  be  parasitic. 

Parasites  gain  entrance  to  the  host  in  many  ways.  The  adult  para- 
site of  some  species  stings  its  eggs  into  the  body  of  the  host,  using  for  this 
purpose  a  sharp  organ  called  the  ovipositor.  This  is  usually  located  at 
the  tip  of  the  abdomen  or  near  it  on  the  underside  of  the  body.  Other 
parasites  fasten  their  eggs  onto  the  surface  of  the  host's  body.  When 
the  young  parasite  emerges  from  the  egg  it  burrows  into  the  host.  In 
other  cases  the  young  parasite  remains  on  the  outside  with  only  a  small 
portion  of  its  body,  including  the  head,  buried  in  the  host. 

The  larvae  of  certain  flies  are  deposited  upon  the  host  and  immedi- 
ately proceed  to  enter  its  body  through  natural  openings  or  by  burrowing 
through  some  tender  tissue. 

129 


Beneficial  Insects 

These  parasitic  larvae  feed  upon  the  blood  of  the  host  insect.  The 
host  in  many  cases  remains  alive  and  functions  naturally  until  the  para- 
site is  fully  mature.  In  the  case  of  some  caterpillars  the  parasite  does 
not  emerge  until  after  the  change  to  the  pupa  has  taken  place. 

Some  parasites  live  only  within  closely  related  insects.  Thus  certain 
kinds  are  parasitic  upon  cutworms  only,  others  upon  grasshoppers  and 
related  insects,  and  still  others  upon  the  eggs  of  certain  insects. 

Since  these  parasites  are  dependent  upon  certain  hosts  for  their 
existence  their  numbers  rise  and  fall  with  the  increase  and  decrease  of 
their  hosts.  This  is  why  some  noxious  insects  become  so  numerous  at 
times.  A  scarcity  of  these  insects  is  followed  by  a  scarcity  of  their  para- 
sites. When  the  parasites  become  very  few  and  favorable  conditions 
exist  for  the  multiplication  of  a  particular  insect  it  often  increases  so 
rapidly  as  to  do  much  damage  before  the  parasites  again  get  the  upper 
hand. 

A.     PREDACIOUS  INSECTS 
1.     GROUND  BEETLES 

(Figs.  1,  2,  3,  20,  21  and  22,  Plate  IX,  Page  27) 

The  popular  name,  "ground  beetle,"  has  been  applied  to  these 
beetles  because  they  are  most  frequently  encountered  running  rapidly 
over  the  ground  or  lurking  under  stones  or  other  objects  lying  on  its  surface. 

The  majority  of  these  beetles  are  shining  black.  However,  some  are 
bright  metallic  green,  dark  blue,  brown  or  even  spotted.  Their  legs  are 
long  and  slender  and  their  movements  rapid. 

Most  of  the  species  are  predacious,  feeding  upon  other  insects  which 
they  capture  either  by  pouncing  upon  them  or  by  chase.  Several  species 
feed  upon  vegetable  matter,  but  their  depredations  are  rarely,  if  ever,  of 
great  economic  importance. 

The  larvae  of  ground  beetles  frequent  the  same  places  as  the  adults, 
and,  like  them,  are  predacious.  Figure  1,  Plate  IX,  Page  27  will  serve 
as  a  typical  example  of  ground  beetle  larvae.  Figure  3,  Plate  IX,  Page 
27  represents  a  very  common,  black  ground  beetle,  while  Figures  20,  21 
and  22,  Plate  IX,  Page  27  represent  the  larva,  pupa  and  adult  of  a 
species  already  mentioned  in  connection  with  the  natural  control  of 
grasshoppers. 

(a)     FIERY  HUNTER 
(Figs.  1  and  2,  Plate  IX,  Page  27) 

The  fiery  hunter  is  one  of  our  largest  ground  beetles  and  can  be 
recognized  by  the  copper  colored  or  golden  spots  on  the  wing  covers. 
This  beetle  (Fig.  2,  Plate  IX,  Page  27)  and  its  larva  (Fig.  1,  Plate  IX, 
Page  27)  are  particularly  fond  of  caterpillars.  By  some  authors  it  is 
known  as  the  "caterpillar  killer."  Many  a  cutworm  has  fallen  a  prey  to 
these  beetles. 

(b)     BOMBARDIER-BEETLES 

The  members  of  one  group  of  ground  beetles  are  provided  with  a 
sack  of  very  volatile  fluid  at  the  tip  of  the  abdomen.  When  pursued, 
this  fluid  is  ejected  with  a  loud  popping  sound  and  as  it  comes  in  contact 
with  the  air  it  is  reduced  to  a  gas  which  appears  like  a  tiny  puff  of  smoke. 
I  he  sharp  report  accompanied  by  the  puff  of  smoke-like  gas  suggested 
the  name  "bombardier-beetles,"  by  which  these  beetles  are  known. 

130 


Beneficial  Insects 
2.     TIGER-BEETLES 

(Figs.  5,  6  and  7,  Plate  IX,  Page  27) 


Fig.    27.     Entrance   to   Burrow  of  Tiger-beetle   Larva. 
There   is   never  any   soil   at   the   entrance   to    these   bur- 


Fig.  28.  Same  Burrow  as  show 
head  of  larva  resting  on  level  wi 
to  seize  a  victim. 


the   surface,    ready 
131 


The  tiger-beetles 
are  common  objects 
about  the  borders  of 
fields  or  on  beaten 
pathways  and  road- 
sides. They  are  lov- 
ers of  sunshine  and 
frequent  exposed  po- 
sitions. 

The  tiger-beetles 
are  the  most  agile 
of  all  beetles,  being 
equally  at  home  on 
the  ground,  where 
they  run  with  amaz- 
ing rapidity,  or  on 
the  wing.  When  ap- 
proached they  take 
flight,  fly  a  short  dis- 
tance, and  invaria- 
bly alight  facing  the 
intruder. 

The  larvae  and 
adults  are  preda- 
cious, feeding  entire- 
ly upon  other  in- 
sects. One  author 
states  that  the  only 
thing  in  common  be- 
tween these  beetles 
and  their  young  is 
their  eagerness  for 
prey. 

The  larva  (Fig. 
5,  Plate  IX,  Page 
27)  is  an  uncouth 
creature  and  spends 
its  entire  existence  in 
a  perpendicular  bur- 
row (Fig.  27,  Page 
131)  in  the  hard 
ground  of  some  path 
or  roadside.  During 
the  day  it  lies  with 
its  head  just  at  the 
surface  of  the  ground 
(Fig.  28,  Page  131), 
its  jaws  open  like  a 
steel  trap,  waiting 


Beneficial  Insects 

for  some  unfortunate  insect  to  pass  near.  When  one  comes  within  reach 
the  jaws  snap  shut  and  the  victim  is  drawn  into  the  burrow  and  devoured. 

In  order  to  prevent  some  stronger  insect  from  dragging  the  young 
tiger-beetle  from  its  burrow,  nature  has  provided  it  with  a  peculiar  anchor 
in  the  form  of  a  hump  on  the  fifth  segment  of  its  abdomen.  This  hump 
is  armed  with  several  curved  hooks  which  fasten  into  the  walls  of  the 
burrow,  thus  making  it  possible  for  the  larva  to  withstand  the  pull  of  a 
powerful  victim. 

The  adults  (Figs.  6  and  7,  Plate  IX,  Page  27)  are  usually  a  metallic 
green  or  bronze  banded  with  light  markings,  from  which  comes  the  name 
"tiger-beetle."  However,  some  are  black,  while  others  are  light,  in  har- 
mony with  the  color  of  the  sand  on  which  they  live. 

3.     LADY-BEETLES  OR  LADY-BUGS 

(Figs.  14,  15,  23  and  24,  Plate  IX,  Page  27;  Figs.  10  and  15,  Plate  II,  Page  13; 
Fig.  14,  Plate  VI I,  Page  23) 

The  lady-beetles,  or  lady-bugs,  as  they  are  commonly  called,  are 
among  the  best  known  and  most  important  predacious  insects. 

Both  the  adults  and  larvae  feed  upon. small,  soft  bodied  insects  and 
insect  eggs. 

These  beetles  have  the  peculiar  habit  of  congregating  in  very  large 
numbers  in  the  fall  of  the  year  just  before  going  into  hibernation.  At 
such  times  they  can  be  scooped  up  by  the  quart  as  they  cluster  about  the 
bases  of  trees  and  shrubs  or  under  stones,  in  layers  many  deep.  Such  a 
congregation  of  the  species  discussed  below  occurred  at  the  very  top  of 
one  of  the  highest  mountain  peaks  near  the  city  of  Denver  in  1916. 

Hippodamia  convergens  (Fig.  15,  Plate  IX,  Page  27)  is  the  com- 
monest of  all  species.  This,  together  with  several  others,  is  especially 
noted  for  the  numbers  of  plant-lice  which  it  destroys.  The  larva  (Fig.  23 , 
Plate  IX,  Page  27)  is  a  common  object  among  colonies  of  plant-lice, 
where  the  pupa  (Fig.  24,  Plate  IX,  Page  27)  is  also  often  encountered 
fastened  to  a  twig  or  leaf.  Other  species  are  especially  useful  for  their 
work  in  orchards,  where  they  devour  scale  insects  which  would  otherwise 
injure  the  trees  and  fruit.  Figure  10,  Plate  II,  Page  13  shows  a  lady- 
beetle  which  feeds  upon  sugar  beet  root-lice.  Figure  15,  Plate  II,  Page 
13  shows  the  larva,  and  Figure  14,  Plate  VII,  Page  23,  the  pupa,  of  this 
same  beetle. 

The  eggs  of  lady-beetles  vary  with  the  species,  as  does  the  place 
selected  for  depositing  them.  Those  of  our  common  forms  resemble 
the  eggs  of  the  Colorado  potato-beetle,  but  are  smaller.  They  are  de- 
posited in  clusters,  the  eggs  standing  on  end.  A  cluster  of  the  eggs  of 
Hippodamia  convergens  is  shown  in  Figure  14,  Plate  IX,  Page  27. 

4.     TRUE  BUGS 

(Fig.  14,  Plate  II,  Page  13) 

The  majority  of  the  true  bugs  are  vegetable  feeders,  and  pests  of  the 
first  magnitude.  However,  several  families  contain  species  which  are 
predacious,  feeding  upon  the  blood  of  other  insects  or  the  higher  animals, 
which  is  sucked  up  through  their  strong,  jointed  beaks. 

132 


Beneficial  Insects 

(a)  ASSASSIN-BUGS 

The  members  of  this  family  are  so  pre-eminently  predacious  that 
they  are  known  as  the  assassin-bugs.  Their  mode  of  attack  is  truly  that 
of  the  assassin.  Approaching  their  prey  by  stealth  or  lying  in  wait  for  it, 
they  pounce  upon  their  victims  and  pierce  them,  oftentimes  in  the  back, 
with  their  beaks  and  proceed  to  drink  up  their  life  blood. 

One  noted  member  of  this  family  feeds  upon  bedbugs  and  is  known 
as  the  masked  bedbug  hunter.  This  insect  infests  houses  where  its  prey  is 

found. 

(b)  AMBUSH-BUGS 

The  bugs  of  this  family  are  called  ambush-bugs  because  of  their 
habit  of  lying  concealed  in  flowers,  especially  those  of  thistle  and  golden- 
rod,  patiently  waiting  for  some  nectar  loving  insect  to  visit  their  ambush. 
The  unlucky  visitor  is  grasped  with  the  much  enlarged  fore  legs  of  the 
ambush-bug  and  impaled  on  its  strong  beak. 

The  common  species  of  this  family  are  yellowish  or  greenish,  marked 
with  dark  bands  and  spots.  The  abdomen  is  broadened  behind,  con- 
cave on  top  and  very  convex  below.  The  forward  pair  of  legs  is  very 
much  enlarged  and  armed  with  heavy  claws  with  which  the  bug's  prey 

is  held. 

(c)     STINK-BUGS 

(Figs.  8  to  13,  Plate  IX,  Page  27) 

The  members  of  the  stink-bug  family  are  furnished  with  glands 
which  secrete  a  very  ill-smelling  fluid  which  escapes  through  two  open- 
ings on  the  under  side  of  the  body. 

While  most  of  these  bugs  feed  upon  vegetables,  some  being  noted 
pests,  several  species  are  predacious. 

The  pictured  soldier-bug  (Figs.  12  and  13,  Plate  IX,  Page  27)  is  noted 
as  a  destroyer  of  potato-beetles,  and  also  feeds  upon  alkali-beetle  larvae. 
The  eggs  (Fig.  8,  Plate  IX,  Page  27,  natural  size,  and  Fig.  .9,  Plate  IX, 
Page  27,  enlarged)  are  placed  on  the  leaves  of  potatoes  and  other  plants 
where  the  insects  fed  upon  by  the  young  are  found. 

When  first  hatched  the  young  are  reddish,  as  shown  in  Figure  11, 
Plate  IX,  Page  27.  The  half-grown  nymphs  appear  as  in  Figure  10, 
Plate  IX,  Page  27.  The  adults  are  of  two  colors,  as  shown  in  the  figures. 

5.     LACE-WINGED  FLIES 

(Figs.  16,  17,  18  and  19,  Plate  IX,  Page  27) 

The  delicate,  green,  lace-winged  fly  or  golden-eyes  (Fig.  19,  Plate  IX, 
Page  27),  as  it  is  frequently  called,  is  a  familiar  object  flitting  about  in 
the  cool  of  dense  foliage,  especially  where  aphids  or  other  small,  soft 
bodied  insects  are  numerous. 

The  eggs  (Fig.  16,  Plate  IX,  Page  27)  are  always  attached  to  the 
surface  of  a  leaf  or  other  object  by  a  hair-like  stalk  about  one-half  inch 
long.  One  author*  states  that  this  is  nature's  way  of  protecting  the 
unhatched  eggs  from  the  newly  hatched  larvae,  which  are  so  exceedingly 
voracious  that  even  their  own  unhatched  brothers  and  sisters  are  not 
safe  when  other  food  is  not  available. 

*Comstock.  "Manual  of  Insects."  page  181. 

133 


Beneficial  Insects 

The  larvae  (Fig.  18,  Plate  IX,  Page  27)  are  common  among  aphid 
colonies.  When  first  hatched  they  devour  these  soft  bodied  insects  at 
the  rate  of  four  or  five  a  day  and  at  the  rate  of  twenty  or  more  a  day 
when  fully  grown.  Because  of  the  numbers  of  plant-lice  they  devour, 
these  spindle-shaped  larvae  are  called  aphis-lions. 

In  feeding,  the  aphis-lion  seizes  its  prey  in  its  long  jaws,  which  are 
so  formed  that  each  pair  makes  a  tube  through  which  the  body  contents 
of  the  aphid  are  sucked  up. 

During  its  existence  as  a  larva  the  lace-winged  fly  probably  con- 
sumes from  300  to  400  plant  lice.* 

Many  other  small  insects  are  eaten  besides  aphids.  In  the  article 
referred  to  in  the  preceding  paragraph,  the  author  lists  ten  insects  be- 
sides several  species  of  plant-lice  as  hosts  of  the  green  lace-wing  of  Cali- 
fornia. Among  these  are  mites,  leaf-hoppers,  scale  insects,  mealy-bugs 
and  psyllids. 

When  the  larvae  are  fully  grown  they  spin  a  white  globular  cocoon 
(Fig.  17,  Plate  IX,  Page  27),  within  which  the  pupal  stage  is  spent.  The 
adult  escapes  by  gnawing  the  end  of  the  cocoon  partially  off  and  pushing 
this  up  as  shown  in  the  figure. 

As  there  are  several  generations  of  the  lace-winged  fly  each  season 
their  importance  as  destroyers  of  injurious  insects  is  difficult  to  estimate. 

6.     WASPS 
(a)     DIGGER-WASPS 

(Figs.  16,  17  and  18,  Plate  VI,  Page  21) 

We  are  so  accustomed  to  considering  wasps  as  creatures  of  quickly 
aroused  temper  who  resent  any  trespassing  in  the  vicinity  of  their  nests 
by  stinging  the  intruder,  that  many  an  innocent  and  beneficial  member 
of  the  wasp  tribe  is  summarily  put  to  death  and  as  a  result  many  a  crop 
pest  continues  its  work  of  devastation. 

There  are  fourteen  families  of  digger-wasps  in  America  north  of 
Mexico.  Many  of  the  members  of  these  render  invaluable  service  to  the 
farmer  and  gardener  by  destroying  the  insects  feeding  upon  his  crops. 
In  habits  many  of  these  represent  a  class  intermediate  between  the  true 
predators,  such  as  the  ground  beetles,  and  the  true  parasites,  which  will 
be  discussed  later. 

(a-1)     FAMILY  SCOLIIDAE 

-  One  member  of  this  family,  Tiphia  inornata,  which  has  been  pre- 
viously mentioned,  burrows  into  the  ground  in  search  of  white  grubs, 
upon  which  it  lays  its  eggs  and  upon  which  the  larvae  are  parasitic. 

I  hese  wasps  are  shining  black  and  about  three-fifths  of  an  inch  long. 
(a-2)     SPIDER-WASPS 

Most  of  the  members  of  this  family  dig  burrows  in  the  ground  which 
are  stocked  with  spiders  upon  which  the  young  wasps  feed.  A  few  spe- 
cies, however,  build  cells  of  mud  which  are  fastened  under  stones  and  in 
other  secluded  places. 

(a-3)     THREAD-WAISTED  WASPS 

The  wasps  of  this  family  can  be  distinguished  from  those  of  the  pre- 
ceding ones  by  the  long  slender  first  segment  of  the  body.  The  peculiar 

No.  14U9i6)W'ldermUth>  "California  Green  Lacewing  Fly."  Journal  of^Agricultural  Research.  Vol.  VI. 

134 


Beneficial  Insects 


Fig.  29.     Nest  of  a  Mud-dauber  taken  from  Rafter  of  an  Out-building 

development  of  this  joint  suggested  the  name  " thread-waisted  wasps" 
by  which  they  are  commonly  known. 

Many  of  these  species  build  large  many  celled  nests  of  mud  on  the 
beams  of  outbuildings  and  about  farm  machinery  stored  under  imple- 
ment sheds  (Fig.  29,  Page  135). 

The  cells  of  these  nests  are  provisioned  with  spiders  and  caterpillars, 
upon  which  the  young  wasps  feed. 

After  dry  spells  these  wasps  are  common  objects  about  mud  puddles 
near  wells  or  after  showers,  where  they  secure  the  mud  required  in  the 
construction  of  their  nests. 

(b)     SOLITARY  WASPS 

(Fig.  15,  Plate  VI.  Page  20) 

These  insects,  many  species  of  which  resemble  the  fiery  tempered 
yellow  jackets,  are  peculiarly  subject  to  persecution  because  of  this 
resemblance. 

Some  of  the  members  of  this  family  are  masons,  building  their  nests 
of  mud;  some  are  miners,  digging  tunnels  in  the  earth  in  which  their 
young  pass  through  the  stages  of  their  development ;  and  still  others  are 
carpenters,  cutting  out  tubular  nests  in  wood,  and  partitioning  these  off 
into  cells  with  mud. 

One  species  (Fig.  15,  Plate  VI,  Page  21)  has  already  been  mentioned 
in  connection  with  the  sugar  beet  webworm  (See  page  44),  and  its  bur- 
row figured  on  page  78  (Fig.  14). 

Another  species  builds  a  jug-shaped  nest,  which  is  attached  to  the 
stem  of  some  plant,  and  provisions  it  with  small  caterpillars. 

B.     PARASITIC  INSECTS 

While  the  predacious  insects  do  much  to  keep  down  the  enemies  of 
cultivated  crops  their  work  is  not  so  effective  as  that  of  the  true  parasites, 
such  as  the  Ichneumon-flies,  Braconids,  and  Chalcis-flies. 

135 


Beneficial  Insects 
1.     ICHNEUMON-FLIES 

(Fig.  5,  Plate  I.  Page  1 1 ;  Fig.  7,  Plate  V,  Page  19;  Figs.  9  and  10,  Plate  VI,  Page  21) 

Many  times  when  our  fields  are  overrun  by  a  pest  we  wish  that  by 
some  magical  power  we  could  destroy  it  and  save  our  crops.  Sometimes 
these  pests  do  disappear  as  if  by  magic.  Many  times  we  little  suspect 
that  the  small  to  medium  sized,  wasp-like  insects,  which  we  observe  hov- 
ering over  the  field,  are  the  friends  that  stood  by  us  in  our  hour  of  need 
and  wiped  out  our  enemies  in  an  incredibly  short  time. 

The  Ichneumon-flies  belong  to  the  same  order  of  insects  as  the  digger- 
wasps,  already  discussed. 

These  flies  have  long  slender  bodies.  That  of  the  female  is  often 
armed  with  a  long  hair-like  ovipositor  (Fig  7,  Plate  V,  Page  19).  This 
is  composed  of  three  parts.  The  central  one  is  a  tube  through  which  the 
eggs  pass,  while  the  two  outer  ones  are  the  sheath  which  protects  the 
ovipositor  proper.  When  the  insect  is  alive  the  three  parts  are  held  close 
together  and  appear  as  a  single  hair-like  organ. 

The  name  "Ichneumon"  was  suggested  by  a  fancied  resemblance  to 
the  Ichneumon  of  Africa,  which  is  a  mammal  belonging  to  the  same 
family  as  the  mink  and  weasel. 

Mention  has  already  been  made  of  two  Ichneumon-flies.  Figure  5, 
Plate  I,  Page  11  is  parasitic  upon  caterpillars  and  was  reared  from  the 
western  army  cutworm.  Figures  9  and  10,  Plate  VI,  Page  21  represent 
a  species  which  destroys  the  alfalfa  looper. 

2.     BRACONIDS 

(Figs.  6  and  7,  Plate    ]  Page  1 1 ;  Fig.  14,  Plate  V,  Page  19) 
Closely  related  to  the  Ichneumon-flies  is  a  group  known  as  the  Bra- 
conids.     The  members  of  this  family  are  small  or  minute  insects. 

Frequently  dead  cater- 
pillars are  observed  cov- 
ered with  small  silken 
cocoons,  or  with  a  mass  of 
these  cocoons  fastened  to 
some  object  near  them 
(Fig.  30,  Page  136).  These 
caterpillars  have  been 
killed  by  the  larvae  of 
some  Braconid  which 
have  gnawed  their  way 
out  of  the  worm  and  spun 
cocoons  in  which  to  com- 
plete their  own  develop- 
ment. 

One  of  the  most  inter- 
esting forms  of  this  family 
belongs  to  the  genus  Aph- 
idus.  These  minute  para- 
sites live  within  the  bod- 
ies of  aphids.  When  ma- 
ture the  parasite  escapes 
through  a  hole  which  it 


Fig. 30.     A  Cabbage-worm  killed  by  the  Larvae 
fv,    ^r^°^id>  the  Cocoons  of  which  are  fastened 
>  the  Window-screen  near  it     (Enlarged) 


136 


Beneficial  Insects 

gnaws  in  its  dead  host.  If  a  colony  of  aphids  is  examined,  especially  in 
the  latter  part  of  the  season,  many  brown  and  much  inflated  individuals 
will  be  observed.  These  are  dead,  and  if  no  hole  is  to  be  seen  on  their 
backs  they  harbor  one  of  these  little  parasites.  Whole  colonies  of  plant 
lice  are  often  wiped  out  by  these  little  insects. 

Figure  6,  Plate  I,  Page  11  represents  a  Braconid  which  is  parasitic 
upon  cutworms.  Figure  7,  Plate  II,  Page  11  represents  a  cocoon  of  this 
same  species. 

Figure  14,  Plate  V,  Page  19  represents  another  Braconid  which  was 
reared  from  a  sugar  beet  webworm  cocoon. 

3.     CHALCIS-FLIES 

(Fig.  8,  Plate  I,  Page  1 1 ;  Fig.  4,  Plate  IX,  Page  27) 

The  Chalcis-flies  are  among  the  smallest  parasitic  Hymenoptera. 
Some  species  are  not  over  one-hundreth  of  an  inch  long.  They  are 
usually  black  with  strong  metallic  reflections.  Some  appear  quite  green, 
while  others  are  yellow.  These  flies  can  be  recognized  by  the  lack  of 
veins  in  the  wings  (Fig.  8,  Plate  I,  Page  11).  This  Chalcis-fly,  as  already 
stated,  is  parasitic  upon  cutworms.  (See  page  44,  and  Figure  4,  Plate 
IX,  Page  27). 

The  greater  part  of  the  parasites  of  small  insects  belong  to  this 
family.  Some  are  parasitic  upon  scale  insects.  One  species  is  the  most 
effective  natural  check  on  the  cabbage-worm. 

Some  Chalcis-flies  are  parasitic  within  the  eggs  of  other  insects. 


137 


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BIBLIOGRAPHY 

The  following  is  a  bibliography  of  the  references  quoted  in  this  Bulletin  and  a  few 
other  publications  on  related  subjects : 

A.  References  Quoted: 

E.  H.  Streckland,  "Control  of  Cutworms  in  the  Prairie  Provinces,"  Circular  No.  6, 
Department  of  Agriculture,  Dominion  of  Canada  (1916). 

Prof.  R.  A.  Cooley,  "Observations  on  the  Life  History  of  the  Army  Cutworm, 
Chorizagrotis  auxiliaris,"  Journal  of  Agricultural  Research,  Volume  VI,  No.  23  (1916). 

G.  E.  Bensel,  "Control  of  the  Variegated  Cutworm  in  Ventura  County,  California," 
Journal  of  Economic  Entomology,  Vol.  IX,  No.  2  (1916). 

J.  I.  Davis,  "Common  White  Grubs,"  Farmers'  Bulletin  No.  543,  U.  S.  Depart- 
ment of  Agriculture  (1913). 

John  E.  Graf,  "A  Preliminary  Report  on  the  Sugar-beet  Wireworm,"  Bulletin  No. 
123,  Bureau  of  Entomology,  U.  S.  Department  of  Agriculture  (1914). 

J.  R.  Parker,  "Life  History  of  the  Sugar-beet  Root-louse,  Pemphigus  betae,"  Journal 
of  Economic  Entomology,  Vol.  VII,  No.  1  (1914). 

J.  R.  Parker,  "Sugar  Beet  Root  Louse  Controlled  by  Irrigation — Four  Years 
Summary." 

J.  R.  Parker,  "Life  History  and  Habits  of  Chloropisca  glabra  Meign.,"  Journal  of 
Economic  Entomology,  Vol.  XI,  No.  4  (1918). 

Harry  B.  Shaw,  "Control  of  the  Sugar-beet  Nematode,"  Farmers'  Bulletin  No.  772, 
U.  S.  Department  of  Agriculture  (1916). 

C.  S.  Scofield,  "The  Nematode  Gajlworm  on  Potatoes  and  Other  Crop  Plants  in 
Nevada,"  Circular  No.  91,  Bureau  of  Plant  Industry,  U.  S.  Department  of  Agricul- 
ture (1912). 

Davis  and  Satterthwait,  "Life-history  Studies  of  Cirphis  unipuncta.,  the  True  Army 
Worm,"  Journal  of  Agricultural  Research,  Vol.  VI,  No.  21  (1916). 

J.  A.  Hyslop,  "The  Alfalfa  Looper,"  Bulletin  No.  95,  Part  VII,  Bureau  of  Ento- 
mology, U.  S.  Department  of  Agriculture  (1912). 

Mr.  Koebels,  Bureau  of  Entomology  Notes,  No.  95-K. 

H.  O.  Marsh,  "Biologic  and  Economic  Notes  on  the  Yellow-bear  Caterpillar," 
Bulletin  No.  82,  Part  V,  Bureau  of  Entomology,  U.  S.  Department  of  Agriculture  (1910). 

Dr.  F.  H.  Chittenden,  "A  Brief  Account  of  the  Principal  Insect  Enemies  of  the 
Sugar  Beet,"  Bulletin  No.  43,  Division  of  Entomologv,  U.  S.  Department  of  Agricul- 
ture (1903). 

Prof.  R.  A.  Cooley,  "Spinach  Carrion  Beetle,"  Journal  of  Economic  Entomology, 
Vol.  X,  No.  1  (1917). 

E.  O.  G.  Kelly,  "A  New  Sarcophagid  Parasite  of  Grasshoppers,"  Journal  of  Agri- 
cultural Research,  Vol.  II,  No.  6  (1914). 

F.  B.  Milliken,  "The  False  Chinch  Bug  and  Measures  for  Controlling  It,"  Farmers' 
Bulletin  No.  762,  U.  S.  Department  of  Agriculture  (1916). 

Boniquit  and  Slake,  "Wild  Vegetation  as  a  Source  of  Curly-top  Infections  of  Sugar 
Beets,"  Journal  of  Economic  Entomology,  Vol.  X,  No.  4  (1917). 

J.  H.  and  A.  B.  Comstock,  "Manual  for  the  Study  of  Insects"  (1909). 

V.  L.  Wildermuth,  "California  Green  Lacewing  Fly,"  Journal  of  Agricultural 
Research,  Vol.  VI,  No.  14  (1916). 

B.  Other  Publications  on  Related  Subjects: 

H.  T.  French,  "The  Beet  Army  Worm,"  Information  Circular  of  the  Colorado 
Agricultural  College. 

E.  D.  Ball,  "The  Beet  Leafhopper  and  the  Curly-Leaf  Disease  That  It  Transmits," 
Bulletin  No.  155,  Utah  Agricultural  College  Experiment  Station  (1917). 

Herbert  H.  Bunzel,  "A  Biochemical  Study  of  the  Curly-top  of  Sugar  Beets,"  Bulle- 
tin No.  277,  Bureau  of  Plant  Industry,  U.  S.  Department  of  Agriculture  (1913). 

147 


E  O  G  Kelly  and  T.  S.  Wilson,  "Controlling  the  Garden  Webworm  in  Alfalfa 
Fields,'"  Farmers'  Bulletin  No.  944,  U.  S.  Department  of  Agriculture  (1918). 

Emst  A.  Bessey  and  L.  P.  Byars,  "The  Control  of  Root-knot,"  Farmers'  Bulletin 
No.  648,  U.  S.  Department  of  Agriculture  (1915). 

C  O  Townsend,  "Curly-top,  A  Disease  of  the  Sugar  Beet,"  Bulletin  No.  122, 
Bureau  of  Plant  Industry,  U.  S.  Department  of  Agriculture  (1908). 

Harry  B.  Shaw,  "The  Curly-top  of  Beets,"  Bulletin  No.  181,  Bureau  of  Plant  Indus- 
try, U.  S.  Department  of  Agriculture  (1910). 

C.  O.  Townsend,  "Field  Studies  of  the  Crown-gall  of'Sugar  Beets,"  Bulletin  No.  203, 
U.  S.  Department  of  Agriculture  (1915). 

F.  B.  Milliken,  "Grasshoppers  and  Their  Control  on  Sugar  Beets  and  Truck  Crops," 
Farmers'  Bulletin  No.  691,  U.  S.  Department  of  Agriculture  (1915). 

Charles  R.  Jones,  "Grasshopper  Control,"  Bulletin  No.  233,  The  Agricultural 
Experiment  Station  of  the  Colorado  Agricultural  College  (1917). 

W.  R.  Walton,  "Grasshopper  Control  in  Relation  to  Cereal  and  Forage  Crops," 
Farmers'  Bulletin  No.  747,  U.  S.  Department  of  Agriculture  (1916). 

E.  D.  Ball,  "How  to  Control  the  Grasshoppers,"  Bulletin  No.  138,  Utah  Agricultural 
College  Experiment  Station  (1915). 

Leland  O.  Howard,  "Insect  Book"  of  the  "New  Nature  Library"  (1914). 

F.  H.  Chittenden,  "Insects  Injurious  to  Vegetables"  (1907). 

E.  D.  Sanderson,  "Insect  Pests  of  Farm,  Garden  and  Orchard." 

J.  R.  Parker,  "Influence  of  Soil  Moisture  upon  the  Rate  of  Increase  in  Sugar-beet 
Root-louse  Colonies,"  Journal  of  Agricultural  Research,  Vol.  IV,  No.  3  (1915). 

C.  P.  Gillette  and  Geo.  M.  List,  "Insects  and  Insecticides,"  Bulletin  No.  210  of  the 
Agricultural  Experiment  Station  of  the  Colorado  Agricultural  College  (1915). 

Singerland  and  Crosby,  "Manual  of  Fruit  Insects." 

E.  W.  Scott,  W.  S.  Abbott  and  J.  E.  Dudley,  Jr.,  "Results  of  Experiments  with 
Miscellaneous  Substances  Against  Bedbugs,  Cockroaches,  Clothes  Moths,  and  Carpet 
Beetles,"  Bulletin  No.  707,  U.  S.  Department  of  Agriculture  (1918). 

Harry  B.  Shaw,  "The  Sugar  Beet  Nematode  and  Its  Control,"  Reprint  from 
"Sugar."  • 

Wm.  H.  White,  "The  Sugar-beet  Thrips,"  Bulletin  No.  421,  U.  S.  Department  of 
Agriculture  (1916). 

H.  O.  Marsh,  "The  Sugar-beet  Webworm,"  Bulletin  No.  109,  Part  VI,  Bureau  of 
Entomology,  U.  S.  Department  of  Agriculture  (1912). 

H.  R.  Cox,  "Weeds:  How  to  Control  Them,"  Farmers'  Bulletin  No.  660,  U.  S. 
Department  of  Agriculture  (1915). 


INDEX 


Abdomen  of  Insects.  .  .29,  30,  43,  46,  104 

Acid,  Arsenous 

Adult  Insects 29,  30 

Agents,  County 2,  4 

Agricultural  College 2,  4 

Air-slaked  Lime 32,  89 

Alaus  oculatus 52 

Alfalfa,  5,  6,  8,  39,  40,  41,  45,  47, 
50,  51,  53,  63,  66,  71,  72,  75, 
76,  81,  82,  84,  85,  86,  94,  98, 

101,  104,  127 

Alfalfa  Cutworm 41 

Alfalfa  Looper 8,  20,  81-84,  136 

Nature  of  Injury 

Methods  of  Control 

Description 82,  83 

Egg 82,  83 

Caterpillar 83 

Cocoon 83 

Pupa 83 

Moth 83 

Life  History 83 

Natural  Enemies 83,  84 

Alfalfa  Webworm 7,  20,  84,  85 

Nature  of  Injury 84 

Methods  of  Control 84 

Description 84,  85 

Worm 84,  85 

Pupa 85 

Moth 85 

Life  History 

Natural  Enemies 85 

Alkali 89,90 

Alkali-beetle  or 

Alkali-bug. ...  7,  8,  22,  29,  89,  90,  92,  133 

Allseed 63 

Amara,  Egg-eating 106 

Amara  obesa 106 

Amaranthus 86 

Ambrosia 86 

Ambush-bug 133 

Annual  Meadow-grass 63 

Antennae  of  Insects 29 

Ants 114 

Aphids  or  Plant  Lice.3, 11 1-1 16,123,134, 137 

Nature  of  Injury 114 

Methods  of  Control 114,  115 

Description 115 

Life  History 115 

Natural  Enemies 115,  116 

(See  also  Plant-lice) 

Abhidus,  Genus 136 

Aphis-lion 26,116,133,134 

Appendix 2,  3,  138-146 

Archylus  abicifere 

Arsenate  of  Lead,  32,  73,  79,  82,  86,  88,  96 


Arsenical  Poisons 33,  86 

Arsenous  Acid 33 

Artificial  Methods  of  Insect  Control  31,  32 

Ash,  White 112 

Ash-gray  Blister-beetle 22,  98 

Asparagus 63,  65,  66,  86 

Assassin-bug 133 

Authocorls  mdanocerus 59 

B 

Bacteria 61 

Bacterial  Diseases 83,  109 

Bait,  Poisoned,  32,  39,  40,  47,  53, 

79,  94,  95 

Banded  Flea-beetle 16,  92,  93 

Description 92 

Egg 92 

Larva 92 

Adult 92 

Life  History 93 

Barley 63,  65,  66 

Beak,  of  Sucking  Insects 29 

Beans 53,  119 

Dwarf  Pea 63 

Lima 63,66,86 

Soy 63,  66 

String 86 

"  Bearded  Roots  " 61 

Bedbugs 133 

Bees 29,30,  78 

Beet  or  Spinach  Leaf-miner. ..  14,  1 10,  1 1 1 

Nature  of  Injury 110 

Methods  of  Control 1 10,  1 1 1 

Description Ill 

Egg. HI 

Miner Ill 

Pupa Ill 

Adult Ill 

Life  History Ill 

"Beet  Weariness " 59 

Beetles,  1,  3,  29,  30,  48,  50,  51,  67, 

78,  88,  105 
See  also: 

Black  Carrion-beetle 

Blister-beetle 

Bombardier-beetle 

Click-beetle 

Colorado  Potato-beetle 

Egg-eating  Amara 

Fiery  Hunter 

Flea-beetles 

Banded  Flea-beetle 
Potato  Flea-beetle 
Three-spotted  Flea-beetle 
Ground  Beetles 
Lady-beetle  or  Lady-bug 
Larger  Sugar  Beet  Leaf-beetle 
or  Alkali-beetle 


149 


INDEX— Continued 


Beet'es — Continued 

Leaf  Beetles 

Leaf-eating  Beetles 

Sacred  Beetle  of  Egypt 

Snapping-beetle 

Tiger-beetle 

Western  Beet  Leaf-beetle 
Beets,  Garden. ..  .63,  66,  86,  88,  99,  110 

Beets,  Stock 8o 

Beets,  Sugar 

(See  Sugar  Beets) 

Beet-seed  Louse,  Black 14,    117-119 

Beneficial  Insects ; . .  .3,  26,  129-137 

Parasitic 3,  43,  52,  135-13/ 

Predacious 3,  43,  52,   130-135 

Bibliography 2,3,  147,  148 

Birds,  43,  45,  46,  5,,  54,  57.  8,,^  ^ 

Biting  Insects 1,  29,  31,  32 

Mouth  Parts  of 29 

Control  of 32 

Biting  Leaf  Feeders 3,  67 

Biting  Root  Feeders 3,  38 

Black  Beet-seed  Louse 14,  1 17-1 19 

Nature  of  Injury 117 

Methods  of  Control 

Description 118 

Wingless  Lice 118 

Puple 118 

Winged  Lice 118 

Life  History 118,  119 

Blackberry 86 

Blackbird 45,81,  108 

Blackbird,  Crow 51 

Black  Blister-beetle 22,  98 

Black  Carrion-beetle 94 

Black  Leaf  40 33,  1 14,  1 17 

Blight 124 

Blight,  Western 124 

Blister-beetle 22,  96-98,  106 

Nature  of  Injury % 

Methods  of  Control % 

Description 97,  98 

Egg 97 

First  Larval  Stage 97 

Second  Larval  Stage 97 

Third  Larval  Stage 98 

Pupa 98 

Adult 98 

Life  History 97,  98 

Blister-beetle,  Ash-gray 22,  98 

Blister-beetle,  Black 22,  98 

Bombardier-beetle 130 

Bordeaux  Mixture 92 

Botrytis  bassiana 87 

Braconids,  3,  10,  18,  43,  77,  135,  136,  137 

Breathing  of  Insects 29 

Brown-cyst 64 

Buckwheat 50 

Bugs,  True,  3,  12,  29,  30,  111,  119, 

122,  132,  133 

Burning 32,  63,  89,  120,  125,  127 

Burning  Bush 118 


Burrowing  Owl 108 

Butcher-bird 54 

Butterflies 29,  30,  67 


C 


Cabbage. 
Cabbage-worm. 


.63,  65,  66,  86,  88 
..136,  137 


California  Devastating  Locust 1 00 

California  Shrike 54 

Canna 86 

Cantaloupe 63,  86 

Care  of  Sprayers 34,  35 

Carrion-beetle,  Black 94 

Carrion-beetle,  Spinach 7  22,  94,  95 

Carrots 66,  86 

Catalpa 66 

Caterpillar  Killer 130 

Caterpillars,  1,  3,  29,  30,  38,  67,  71, 

81,  130,  135,  136 

Caterpillars,  Leaf-eating 67 

Caterpillar,  Yellow-bear 8,  18,  86,  87 

Caterpillar,  Zebra 8,  14,  87,  88 

Cauliflower 63,  66,  86 

Celery ..  .63,  66,  86 

Chalcis-fly 3,  10,  26,  43,  44,  135,  137 

Chloropisca  glabra 59 

Chenopodium 86 

Cherry 66,  86 

Chiggers 106 

Chinch  Bug 119 

Chinch  Bug,  False,  6,  24,  29,  119-121,  123 

Chitin 30 

Chrysalis 30 

Classification  of  Insects 3,31 

Clean  Culture,  1.  32,  91,  94,  104, 

111.  120,  122,  125,  127 

Click-beetle 52,  53,  54 

Clover 40,  50,  66 

Crimson 63 

Sweet 8,63,66,82 

"      White 63 

Clover  Leaf-hopper 24,  126-128 

Nature  of  Injury 127 

Methods  of  Control 127 

Description 127 

Egg 127 

Nymph 127 

Adult 127 

Life  History 127,  128 

Cocoon 44,  45,  76,  83,  85,  87,  136 

Colorado  Potato-beetle 89,  132 

College,  Agricultural 2,  4 

Colored  Plates 1,  2,  3,  4,  1 1-27 

Common  Mallow 125 

Compound  Eye  (of  Insect) 76 

Contact  Poisons 32,  33,  1 14 

Control  of  Insects 31-33 

Natural  Methods 31,  32 

Cultural  Methods 31,  32 

Artificial  Methods 31,  32,  33 

Control  of  Biting  Insects 32,  33 

Control  of  Sucking  Insects 33 

Coopers  Hawk 109 


Corn. 


.50,  53,63,  65,66, 


99 


150 


INDEX— Continued 


Com  Root-louse 38 

Com  Root-worm 31,38 

Cost  of  Spraying 47,  74 

Cottonwood 56,  58 

Cottonwood,  Narrow  leaf 57,  58,  113 

County  Agents 2,  4 

Cow  Pea 63,  66 

Cress 63 

Crickets,  Field 3,  16,67,  109,  110 

Crimson  Clover 63 

Crop  Rotation,  1,  31,  50,  53,  57,  62,  63,  65 

Crow 51.  54 

Crow  Blackbird 51 

Cucumbers 63,  66,  93 

Cultural  Methods  of  Insect  Control         3 1 

Curly-top 8,  24,  60,  61,  124,  125 

Currants 86 

Cutworms,  3,  4,  5,  20,  26,  38-48,  87, 

130,  137 

Nature  of  Injury 38,  39 

Where  to  Look  for  the  Worms ...  -  *  39- 

Methods  of  Control 39,  47 

Cutworm,  Alfalfa 41 

Cutworm,  Pale  Western,  10,  41,  45,  46,  47 

Cutworm,  Variegated 8,  22,  47,  48 

Cutworm,    Western   Army,    8,    10, 

41-45,  46,  47,  88,  136 
D 

Dahlia :.   -      86 

Dandelion 63 

Destruction  of  Summer  Hosts 117 

Destruction  of  Weeds 71,  72 

Development  of  Insects 3,  29,  30 

Differential  Hopper 16,  100 

Digger-wasp 20,  43,  44,  45,  134,  136 

Digger-wasp  enemy  of  Cutworms. .  44,  45 

Disc 50,53 

Discing 31,  40,  50,  53,  103,  104 

Diseases  of  Insects. ..  .59,  83,  88,  109,  121 

Dock  (Rumex) 86 

Duck  Hawk 109 

Dwarf  Pea  Bean 63 

E 

Eelworms 38,  59,  64 

Egg-eating  Amara 106 

Egg  Plant 

Eggs,  Grasshopper % 

Eggs  of  Insects 

Elis  sexcincta 

Elm 

Empusa  aphidis 


97,  104,  105 

30,  31 

52 

66 

59 

Emp>usa  grylli 109 

Emulsion,  Kerosene 33,  1 14,  122 

Euonymus  Sp 118 

Eutettix  strobi 24,  128 

See  note  opposite  Clover  Leaf- 
Hopper  in  Appendix 
Eyes  of  Insects 76 


Fall  Plowing 31.  40,  50,  53 

False  Chinch  Bug ...  6,  24,  29,  1 1 9- 1 2 1 ,  1 23 

Nature  of  Injury 1 19 

Methods  of  Control 120,  121 


Description 121 

Egg 121 

Nymph 121 

Adult 121 

Life  History 121 

Natural  Enemies 121 

Fanweed 6 

Feelers  of  Insects 29 

Field  Crickets 3,  16,  67,  109,  1 10 

Fieldmen 2,  4 

Fiery  Hunter 26,  130 

Flea-beetle 7,  16,  29,  91-93.  % 

Nature  of  Injury 91 

Methods  of  Control 91,  92 

Flea-beetle,  Banded 16,  92.  93 

Flea-beetle,  Potato 16,  93 

Flea-beetle,  Three-spotted 16  93 

Flesh-flies 105 

Flesh-fly  parasite  of  Grasshoppers  16  105 

Flies 30 

Flies,  Chalcis.  ..3,  10,  26,  43,  44,  135/137 

Flies,  Flesh 105 

Flies,  Ichneumon  3,  10,  20,  43,  83,  135,  136 

Flics,  Lace-winged 3,  26,  1 16,  133,  134 

Flies,  Parasitic 52,  81 

Flies,  Robber 20,  78 

Flies,  Syrphus 20,  59,  1 16 

Flies,  Tachina 18,  20,  77,  85,  87 

Flies,  Two-winged 20,  29,  30,  111,  121 

Flour,  Low  Grade 32,  89 

Food  Plants  of  Insects 32 

Fossores 44 

Fox  Tail,  Green 63 

French  Bug 89 

Fumigants,  Soil ! 65 

Fungi 94 

Fungous  Diseases  of  Insects,  59,  88. 

109,  121,  123 
Furrow  Trap 72,  79,  82 


Galllardia  pulchella 121 

Gallwcrm    (See  Root-knot  Nema- 
tode  or  Gall  worm) 

Garden  Beets 63,  1 10 

Garden  Peas 63 

Gas  Tar 53 

General  Discussion  of  Insects 29-33 

Giant  Thorn-headed  Worm 50 

Golden-eye  (See  Lace-winged  Fly)26,  133 

Golden-glow 115 

Goldenrod 98,  133 

Gooseberry 86 

Gordian  Worm 107 

Goshawk 109 

Grain,  5,  8,  38,  39,  45,  50,  53,  79, 

80,94,  101,  119 

Grapes 86 

Grass 49,  54,  80,  99,  123 

Grasshopper  Eggs.  16,  26,  96,  97.  104.  105 
Grasshoppers,  1.  3,  8,  16,  18,  29,  30, 

31,98-109,  130 

Nature  of  Injury 101 

Methods  of  Control 101-104 


151 


INDEX— Continued 


Grasshoppers—  Continued 
Eggs              16,96 

1 

,  97,  104,  105 
.  .  104,  105 
...105-109 
109 
....  108,  109 
94 
63 
116,  117,  118  i 
116 
116  i 
116  j 
116 

I 
Ichneumon-fly  3,  43,  83,  135,  136 
Ichneumon-fly  parasite  of  Alfalfa 
Looper  20,  83.  136 
Ichneumon-fly  parasite  of  Western 
Army  Cutworm  10,  43,  136 
Identification  of  Insects  1,2 

Life  History  
Natural  Enemies  
Diseases  of.  

Great  Homed  Owl  
Green-berried  Nightshade.  .  . 
Green  Fox  Tail  
Green  Peach-aphis  24, 
Nature  of  Injury  
Methods  of  Control  
Description  

Index  2,  3,  149-157 

Insects  1,3,29-33 
Abdomen  of  29,  30,  43,  46,  104 

^ult                                        29,  30 

Beneficial  Insects  3,  26,  129-137 
Parasitic  3,  43,  52,  135-137 

Winged  Lice  
Wingless  Lice  
Females  

....116,  117  i 
....116,  117 
117 
117 

Predacious                 3   43   52    130-135 

Biting                                 1    3   29  31    32 

Males 

Biting  Leaf  Feeders                           3   67 

117 

Life  History  ..116,117 
Ground  Beetles  26  43,  54,  81.  105. 

Breathing  of  '  29 
Classification  of  3,  31 
Control  of  31-33 
Control  of  Biting  Insects  32,  33 
Control  of  Sucking  Insects                   33 

See:  Bombardier-beetle 
Egg-eating  Amara 
Fiery  Hunter 

Ground  Squirrel  

108,  130 
108 

Development  of                           3   29  30 

Diseases  of  59,  83,  88,  109,  121 
Eggs  of                                            30  31 

Grubs  30,  31,  38,  43,  45,  48,  50,  97 
Grubs,  White,  3,  5,  10,  31,  38,  48-52, 
53,  54,  97.  134 
Gyrfalcon  109 

Eyes  of         76 

Feelers  of      29 

Food  Plants  of  32 
General  Discussion  of  29-33 
Head  of  29 
Heart  of  46 
Hibernation  of  32 
Identification  of  1,2 
Integument  of  30 

H 
Hair  Snake  

107 

Hair  Worm  

..16,  107,  108 

Hand  Pickinp 

117    120   122 

36 

£^sof  29,  31 

50  53 

rvae  of  29,  30 
Leaf-eating  79 
Leaf  Feeders  3,  31,  67,  111 

31    103    104 

106 
108   109 

J-Tav»/k 

Biting  3,  67 

Hawk,  Sharp-shinned  

109 
109 

Sucking                                         3    111 

Legs  of  29 

Hawk  Swainson  s 

109 

Metamorphosis  of  29,  30 
Methods  of  Control  of                 3   31-33 

Head  of  Insects  
Heart  of  Insects 

.:....         29 
46 
86 
119 
63 
59 
119 
32 
132 
50 
86 
37 
114 
.  .99,  102,  103 
63 

Artificial  31,  32,  33 
Cultural  31,  32 

Natural  31 
Molting  of  30 
Mouth  Parts  of  29,  30,  3  1 
Natural  Enemies  of,  31,  43,  44, 
45,  46,  51,  52,  54,  59,  77,  78, 
81,83,84,85,87,  88,  105,  106, 
107,   108,   109,    115,    116,    121, 
123,  129-137 

Parasitic  Insects  (Beneficial),  3, 
43,  52,  135-137 

Predacious  Insects  (Beneficial),  3, 
43,  52,  130-135 

Proboscis  of  29,  76 
Prolegs  of  29 
"Props"  of  29 
Pupa  of..                                                30 

Hemp  
Heterodera  schachtii  
Heterohtera  
Hibernation  of  Insects  
Hibbodamia  convergent.  .  .  . 
Hogs,  Pasturing  with  
Hollyhock  
Home-made  Sprayer  
Honey  Dew  
Hopper  Dozer  
Hops  

Horseradish  

65,66 

Horse  Bean 

119 

"Hunger  Roots"  

61 

Hyacinth 

86 

Hymenobtera.  .. 

137 

152 


INDEX— Continued 


Insects — Continued 

Root  Feeders 

Biting 

Sucking 

Scales  of 

Skin  of 

Spiracles  of 

Structure  of 

Sucking  Insects.  .  .  .3,  29,  31, 

Sucking  Leaf  Feeders 

Sucking  Root  Feeders 

Thorax  of 

Tracheae  of . . . 

Wings  of 

Insecticides 

Insect  Powders 

Integument  of  Insects 

Introduction  to  Bulletin 

Irrigation 1 ,  56,  62 

Early 

Fall 

Spring 


,  31,  38,67 
.  ...     3,38 
.  ...     3,55 
..134,  137 
30 
29 

.  . . .     3,  29 
32,33,  119 

3,  111 

.  ...  3,55 
29 

.';;:,-•  29 

29 
32 
33 
30 
1-8 

,  72,  84,  92 
56 

.  . . .  56,  57 
. .  56,  57 


Jaws  of  Insects. 
June -bug 


29,  31 
48,  50 


K 


Kafir 65,  66 

Kale 63,65,66 

Kansas  Mixture,  39,  40,  94,  101,  102,  103 

Formula  for 39,  101 

How  to  Make 39,  40,  101 

How  to  Apply 40,  102 

Time  to  Apply 40,  101,  102 

Treating  Fields  Before  Planting        40 

Where  to  Apply 102 

Kerosene 96,  103,  114,  120 

Kerosene  Emulsion 33,  114,  122 

Key  for  Determining  Insect  Injury 

to  Sugar  Beets 1,  2,  3,  4,  5-8 

Explanation  of 4 

Knapsack  Sprayer 36,  89 

Kohl-rabi...  63 


Lace-winged  Fly 3,26,  116,  133,  134 

Lady-beetle 22,  26,  59,  115,  132 

Lady-beetle  enemy  of  Sugar  Beet 

Root-lice 12   59 

Lady-bug 132 

Lamb's-quarters,  69,  71,  75,  86,  93, 

94,  111,  128 

Lantern  Trap 47 

Larger  Sugar  Beet  Leaf-beetle,  or 

Alkali-beetle. .  .  .7,  8,  22,  89,  90,  92,  133 

Nature  of  Injury 89 

Methods  of  Control 89,  90 

Description 90 

Egg 90 

Larva 90 

Pupa 90 

Beetle 90 

Larvae  of  Insects 29,  30 

Late  Planting 32,  41 


Laundry  Soap 114 

Lead,  Arsenate  of,  32,  73,  79,  82,  86,  88,  % 

Leaf-beetle,  Western  Beet 22,  90,  91 

Leaf  Beetles 88,  89,  91 

Leaf-eating  Beetles 88,  89,  % 

Leaf-eating  Caterpillars 67 

Leaf-eating  Insects 67,  79 

Leaf  Feeders 3,31,67,  111 

Biting 3,  67 

Sucking 3,  111 

Leaf-hopper,  Clover 24,  126-128 

Leaf-hopper,  Rose 123 

Leaf-hopper,  Sugar  Beet.  .  .8,  24,  123-126 

Leaf-hoppers 7,  111,  123-128 

Leaf-miner,  Beet  or  Spinach .  .  14,  110,  111 

Leaf-miners 1,  3,  67,  1 10,  1 1 1 

Legs  of  Insects 29 

Lentils 63 

Lesser  Migratory  Locust 100 

Lettuce 63,  66 

Lima  Beans 63,  66,  86 

Lime 33,63,89 

Lime,  Air  Slaked 32  89 

Lime,  Quick. 33,  63 

Lime-sulphur  Mixture. .  .32,  115,  116,  117 

Live  Hopper  Machine 103 

Live  Stock 40,  55,  62,  74,  102 

Poisoning  of 40,  74 

Locust,  California  Devastating. ...        100 

Locust,  Lesser  Migratory 100 

Locust  Mite 18,  106,  107 

Locust,  Red-legged 16,  100 

Locust,  Rocky  Mountain,  98,  100, 

101,  106,  107 

Love -grass 121 

Low  Grade  Flour 32,  89 

Loxostege  similar  is 84 

Lupine,  Yellow 63 

M 

Macrosiphum 115 

Maggots 30,  77 

Mallow,  Common 125 

Mangels 110 

Manuring 1 

Masked  Bedbug  Hunter 133 

May-beetle 48,  51 

Meadow 5,  49,  51,  52,  53,  54 

Meadow-grass,  Annual 63 

Meadow  Lark 45,  81 

Meadow  Oat-grass,  Tall 63 

Mealy-bug •. 134 

Mechanical  Methods  of  Insect 

Control % 

Metamorphosis  of  Insects 29,  30 

Methods  of  Control  of  Insects ....  3,  3 1-33 

Artificial 31,  32,33 

Cultural 31,  32 

Natural 31 

Mice 108 

Microgaster  Sp .    :10 

Millers 38,  67 

Millet 63 

Milo 65,66 

Miners,  Leaf  (See  Leaf-miners) 


153 


INDEX— Continued 


32 

..18,  106,  107 
..29,  106,  134 
121 

30 

86 
29  30,  67,  78 

38 


63 


.57,  58,  .113 


Miscible  Oils 

Mite,  Locust 

Mites 

Mollugo  verticillata 

Melting  of  Insects 

Morning-glory 

Moths 

Moths,  Owlet 

Mouth  Parts  of  Insects .  .  . 

Mowing 

Mud-dauber 

Muskmelon 

Mustard • 

N 

Narrow-leaf  Cotton  wood . . . 

Natural  Enemies  of  Insects,  31,  43, 

44,  45,  46,  51,  52,  54,  59,  77, 

78   81    83    84,  85,  87,  88,  105, 

106,   107,   108,   109,   115,   116, 

121,  123,  129-137 

Natural  Methods  of  Insect  Control  31,  32 
See:   Burning.  .32,  63,  89,  120,  125,  127 
Clean  Culture,  32,  91,  94, 

104,  111,  120,  122,  125,  127 
Crop  Rotation,  31,  50,  53, 

57,  62,  63,  65 
Destruction  of  Summer 

Hosts 117 

Destruction  of  Weeds 71,  72 

Discing..31,  40,  50,  53,  103,  104 

Hand  Picking 117,  120,  122 

Harrowing.... 31,  50,  53,  103,  104 

Irrigation 56,62,  72,84,92 

Late  Planting •.  .  .  32,41 

Mechanical  Measures 96 

Mowing 82,  84 

Picking  Infested  Leaves  .  .        110 
Plowing,  31,  32,  40,  50,  53, 

-    56,  57,  104 

Rolling 40 

Scattering '     91 

Sticky  Shields 120 

Nematode 6,  59-66 

Root-knot    Nematode    or    Gall- 
worm 3,6,  64-66 

Sugar  Beet  Nematode.  .3,  6,  14, 


Worm 

Pupa 

Moth 

Life  History 

Natural  Enemies .  . 


. .  45,  46 
46 

46 
46 
46 


Parasites 43,  44,  129,  130,  135 

Parasitic  Flies 52,  81 

Parasitic  Insects 3,  43,  52,  135-137 

'•>9  30   31    !   Paris  Green,  32,  34.  35,  39,  40,  47, 
'  '  82'  84  53,  68,  70,  72,  73,  74,  79,  82, 

'135  86,  88,  89,  92,  96,  101 

66  |   Paris  Green  Anplied  Dry 32,  89 

Paris  Green,  Caution  Regarding. . .          37 

Parsnips 63,  86 

Pasture 

Pasturing  with  Hogs 
Pea  Bean,  Dwarf. .  . 

Peach 

Peach-aphis,  Green  . 

Peanuts 

Peas 

Cow 

Garden 

Sweet 

Pennycress 

Peppergrass 

Pheasants 

Picking  I  ifcsted  Leaves 

Pictured  Soldier-bug 

Pigweed 

Pigweed,  White ~ 

Pimply  Potatoes 

Pinks 

Plant-bug.  Tarnished. .  .  . 
Plant-lice,  3,  7,  29,  30,  " 

Nature  of  Injury . 


Nicotine  Sulphate.  
Nightshade,  Green-berried  
Nymphs  

0 
Oats                                       63   65 

121 

94 
30 

66   101 

Oils,  Miscible  
Oils,  Soluble  
Onions  
Outline  of  the  Bulletin  
Ovipositor  43, 
Owl,  Great  Horned  
Owlet  Moths  

32 
33 
66 
.  1,2,  3 
129,  136 
108,  109 
38 

Owls  
P 

108,  109 

5   49,  52,  53,  54,  80 

50 

63 

66,  116 

.24,  116,  117,  118 

86 

.50,63,  66,  86,  99 

63,  66 

63 

63 

121 

. .119,  121 

5 

110 

133 

Ill 

93 
63 

..6,  122,  123 
-116, 132,134,  137 
.        114 

114,  115 
115 
115 

115,  116 
.  32,  41 

PlowingTl,  31,  32,  40,  50,  53,  56,  57,  104 

Plowing,  Fall 31,  40,  50,  53 

Plum 116 

Poison 72,  79,  82,  84,  86,  92,  96,  1 14 

Poisoned  Bait,  32,  39,  40,  47,  53,  79,  94,  95 

40,  74 

....  33,  86 
32,  33,  114 

32,  114 

118 

....89,  133 
....89,  132 
....   16,93 
93 


Methods  of  Control. 

Description 

Life  History 

Natural  Enemies. .  . 
Planting,  Late. 


Pale  Western  Cutworm. .  10,  41,  45,  45,  47 
Description. ." 45,  46 


Poisoning  Stock. 

Poisons,  Arsenical 

Poisons,  Contact 

Poisons,  Stomach 

Poppy 

Potato-beetle 

Potato-beetle,  Colorado 

Potato  Flea -beetle 

Description 

Larva 93 

Adult 93 

Life  History 93 

Potatoes,  45,  50,  53,  63,  65,  66,  86, 

93,96,  133 

Potatoes,  Pimply 93 

Poultry 40,  85,  102,  104 

Poverty-weed 91 ,  92 

Predacious  Insects 3,  43,  52,  130,  135 


154 


INDEX— Continued 


Proboscis  o!  Insects 

Prolegs  of  Insects 

"Props"  of  Insects 

Psyllids 

Pumpkin 

Pupa  of  Insects 

Puparium 

Pyrgota  undata 

Q 
Quick  Lime 


29,  76 

29 

1  >4 

£6,  86,  94 

30 

30 

52 

.  .  33,  63 


Rabbit  Brush 46 

Radish 63,66,  86,  121 

Rape 63,  66 

Raspberry 86,  119 

Red-headed  Woodpecker 108 

Red-legged  Locust 16,  100 

Red  Top 65,  66 

Reference  Figures,  Explanation  of  2 

Repellents 33 

Rhubarb 86,  87 

Robber-fly 20,  78 

Robin 45 

Rocky  Mountain   Locust,   98-100, 

101,  106,  107 

Rolling 40 

Root  Feeders 3,  31,  38,  67 

Biting  Root  Feeders 3,  38 

Sucking  Root  Feeders 3,  55 

Root -knot  Nematode  or  Gallworm 

3,  6,  64-66 

Nature  of  Injury 64 

Methods  of  Control 65 

Life  History 65,  66 

Root-louse 38,  55 

See :   Corn  Root-louse 

Sugar  Beet  Root-louse 

Root-worm,  Com 31,38 

Rose  Leaf-hopper 123 

Roses 123 

Rotation .'1,  31,  50,  53,  57,  62,  63,  65 

Rumex  (Dock) 86 

Russian  Thistle,  69,  71,  75,  86,  90,  93,  98 

Rutabaga 63 

Rye 63,  65,  66 


Sacred  Beetle  of  Egypt 

Salsify 

Saltbush 

Scale  Insects 

Scattering  Insects 

Scoliidae 

Scorpions 

Seed  Treatment 

Sharp-shinned  Hawk 

Sheep,  Pasturing  with 

Shepherd  's-purse 

"Shot  Holes" 

Shrike,  California 

Shrubs 

Skin  of  Insects 

Skip-jack 

Skunk. . . 


.  .  48,  49 
66 

90 

134,  137 

91 

134 

106 

53 

109 

62,  63 

6,  119,  120,  121 

91 

54 

...88,  115,  118 

30 

52 

..  51,  54 


Skunk,  Spotted.. 
Snapping-beetle . 

Soap 

Soap,  Whale  Oil . 
S  -ap,  Laundry.  . 

bod 

Soil  Fumigants. 


54 

52 

33,  114,  121 

33,  114,  120,  121 

114 

5 

65 


Solanum  rostratum 86 

Soldier-bug,  Pictured 133 

Solitary  Wasp 20,  77,  78,  135 

Solitary  Wasp  enemy  of  Sugar  Beet 

Webworm 77,  78,  135 

Soluble  Oils 33 

Sorghum 63,  65,  66 

Soy  Beans 63,  66 

Spanish-fly '  % 

Spanish  Needle 86 

Sparrow  Hawk 109 

Spiders 29,  106,  135 

Spider-wasp 134 

Spinach 63,  66,  94 

Spinach  Carrion-beetle 7,  22,  94,  95 


Nature  of  Injury.  . . 

Method  of  Control 

Description 


94 
94,95 
95 


95 
95 
95 

95 
95 
110,  111 


Larva 

Pupa 

Adult 

Life  History 

Spinach  Leaf-miner 

(See  Beet  or  Spinach  Leaf-miner) 

Spindle  Tree 118 

Spiracles  of  Insects 29 

Spotted  Skunk 54 

Sprayers 33-37 

Care  of  Sprayer 34,  35 

Hand  Sprayer 36 

Home-made  Sprayer 37 

Knapsack  Sprayer 36,  89 

Testing  of  Sprayer 35 

Traction  Sprayer 33,  34,  47,  73 

Spraying,  32,  35,  47,  73,  74,  79,  89, 

91,  116,  117,  120 

Spraying,  Cost  of 47,  74 

Spraying,  Winter 117 

Squash 66,  86,  94 

Squirrel,  Ground 108 

Stack  Bottoms 80 

Stacking  Grounds 80 

Sticky  Shields 120 

Stink-bug 119,  133 

Stink-bug  enemy  of  Potato-beetle       133 

Stink-grass 121 

Stomach  Poisons 32,  114 

Strawberry 50,  65,  66 

Strawberry  Bush . 118 

String  Beans 86 

Structure  of  Insects 3,  29 

Sucking  Insects 29,  31,  32,  33,  119 

Control  of 33 

Mouth  Parts  of 29,  3 1 

Sucking  Leaf  Feeders 3,  111 

Sucking  Root  Feeders 3,55 


155 


INDEX— Continued 


Sugar  Beets,  1,  2,  3,  4,  5,  7,  45,  50, 
53  55,  57,  63,  75,  82,  85,  86, 
94  96,  101,  110,  119,  122,  123, 

125,  127,  128 
Sugar  Beet  Leaf-hopper. ...  8,  24,  123-126 

Nature  of  Injury 124,  125 

Methods  of  Control 125 

Description 126 

Egg }26 

Nymph 

Adult 126 

Life  History ' 126 

Sugar  Beet  Nematode,  3,  6,  14,  31, 

38,  59-64,  65 

Nature  of  Injury 61 

How  Spread 61,  62 

Methods  of  Control 62,  63 

How  to  Prevent  Spread 62 

How  to  Check  Multiplication.         63 

Description 64 

Egg 64 

Larval  Stages 64 

Adult 64 

Brown-cyst  Stage 64 

Life  History 64 

Sugar  Beet  Root-louse,  3,6,  12,  38, 

55-59,  111.  113 

Nature  of  Injury 55 

Methods  of  Control 55,  57 

Description 57,  58 

Egg 57 

Ftmales 57 

Hibernating  Lice 58 

Males 57 

Stem-mother 58 

Winged  Lice 57,  58 

Winged  Migrants 58 

Life  History 57,  58 

Natural  Enemies 59 

Sugar  Beet  Webworm,  7,  18,  67-78, 

135,  137 

Nature  of  Injury 68-71 

Methods  of  Control 71-73 

Description 74,  75 

Egg 74,  75 

Worm 75 

Pupa 75 

Cocoon 75 

Moth 75 

Life  History 75-77 

Natural  Enemies 77,  78 

Why  Growers  do  not  Spray. ....  73,  74 

Sugar  Beet  Wireworm 53 

Sulphate,  Nicotine 121 

Sunflower ; 63 

Swainson's  Hawk 109 

Sweet  Clover 8,  63,  66,  82 

Sweet  Potatoes 65,  66  86 

Swine 50 

Syrphus-fly 59,  1 16 

Syrphus-fly  enemy  of  Sugar  Beet 
Root-louse 20,  59 


Tachina-flies 77,85,87 

Tachina-fly  parasite  of  Alfalfa 

Webworm 20,  85 

Tachina-fly  parasite  of  Sugar  Beet 

Webworm 18,  77 

Tall  Meadow  Oat-grass 63 

Tarnished  Plant-bug 6,  122,  123 

Nature  of  Injury 122 

Methods  of  Control 122 

Description 122,  123 

Egg        122 

Nymph 122,  123 

Adult. 123 

Life  History 123 

Natural  Enemies 123 

Testing  of  Sprayers 35 

Thorax  of  Insects 29 

Thread- waisted  Wasp 134,  135 

Three-spotted  Flea-beetle 16,  93 

Ticks 29,  106 

Tiger-beetle 26,  76,  131,  132 

Tiger-moth,  Virginia 87 

Timothy 5,63,65,66 

Tibhia  inornata 52,  134 

Tobacco 114 

Tobacco  Decoction 115 

Tobacco  Preparations 33 

Tomatoes 63,  65,  66 

Tracheae 29 

Traction  Sprayer 33,  34,  47,  73 

Trees 115 

True  Army  Worm 10,  78-81 

Nature  of  Injury 79 

Methods  of  Control 79,  80 

Description 80,  81 

Egg 80 

Worm 80 

Pupa 80 

Moth 80,81 

Life  History ' 81 

Natural  Enemies 81 

True  Bugs,  3,  12,  29,  30,  59,  111,  119, 

122,  132,  133 
A  species  of  True  Bug  which  preys 

upon  Sugar  Beet  Root-lice 59 

Tumble-bug 48 

Turkeys 104 

Turnips 63,  86,  88,  99,  101,  121 

Two-lined  Hopper 16,  100 

Two-winged  Flies 20,  29,  30,  111,  121 


Variegated  Cutworm 
Nature  of  Injury 
Methods  of  Control 
Description 
Egg 
Worm 
Moth 

Life  History 
Verbesina 
Vetch 
Virginia  Tiger-moth 


8,  22,  47,  48 
47 
47 

47,  48 
47 
48 
48 
48 
86 

63,  66 
87 


156 


INDEX— Concluded 


w 


Waahoo  (or  Wahoo) 118 

Wasps 3,  29,  30,  44,  45,  134,  135 

Digger-wasp.  .  .  .20,  43,  44,  45,  134,  136 

Solitary  Wasp 20,  77,  78,  135 

Spider-wasp 134 

Thread-waisted  Wasp 134,  135 

Watermelon 66,  86 

Webworm,  Alfalfa  (See  Alfalfa  Web- 
worm) 

Webworm,  Sugar  Beet  (See  Sugar 
Beet  Webworm) 

Weeds 5,6,  71,  72,89,91 

Western    Army    Cutworm,    8,    10, 

41-45,  46,  47,  88,  136 

Description 41 ,  42 

Worm 41 

Pupa 41 

Moth 41,42 

Life  History 42,  43 

Natural  Enemies 43-45 

Western  Beet  Leaf-beetle 22,  90,  91 

Description -90 

Nature  of  Injury .  . . . 90 

Methods  of  Control 91 

Western  Blight 124 

Whale  Oil  Soap 33,  114,  120 

Wheat 63,  65,  66 

"Whiskered  Beets" 61,  124 

White  Ash 112 

White  Clover 63 

White  Grubs,  3,  5,  10,  31,  38,  48-52, 

53   54,  97,  134 


Nature  of  Injury 

Methods  of  Control 

Life  History 

Natural  Enemies 

White  Pigweed 


49,  50 
50 
51 

51,  52 
111 


Why  Growers  do  not  Spray 73,  74 

Willow 50 

Winged  Lice 57,  58 


Wings  of  Insects 29 

Winter  Spraying 117 

Winthemia  Sp 81 

Wireworm 3,  5,  10,  31,  38,  50,  52-54 

Nature  of  Injury 52   53 

Methods  of  Control 53 

Description 53,  54 

Worm 53 

Pupa 54 

Beetle 54 

Life  History 54 

Natural  Enemies 54 

Woodpecker,  Red-headed 108 

Worms 30,  41,  43,  44,  45,  46,  47,  48 


Yellow-bear  Caterpillar 8,  18,  86,  87 

Nature  of  Injury 


Methods  of  Control. 
Description 

Egg 

Caterpillar 

Pupa 

Moth 

Life  History 

Natural  Enemies 

Yellow  Jacket 

Yellow  Lupine 


86 
87 
87 
87 
87 
87 
87 
87 
135 
63 


Zebra  Caterpillar 8,  14,  87,  88 

Nature  of  Injury 
Methods  of  Control 
Description 

Egg 

Caterpillar.... 

Moth I 

Life  History 

Natural  Enemies... 


157 


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